The Marxist leaders of Angola have been arguing in rising tones of frustration recently that a generation of U.S. misreadings of their country is only being further compounded by the Reagan administration.

The United States has made withdrawal of the "destabilizing" Cuban forces that back the Angolan government a condition to the diplomatic relations sought by Angola. But Angolan officials make it quite clear that they think there is only one destabilizing force in this part of the world -- South Africa.

"The problem on U.S. relations isn't on the Angolan side. It's on the American side," said Vice Foreign Minister Vennacio do Moura. "Those who are preoccupied by the presence of foreign troops in Angola," he said, "must first be preoccupied by the presence of South African troops in Angola, because the Cuban presence is a consequence of Angola's efforts to counter South African troops."

Do Moura repeated Luanda's stand that the Cubans will leave Angola once the South African threat disappears, and his call for better U.S. relations was echoed by the other Angolan officials who agreed to be interviewed by an American reporter.

It was unclear whether the views of these officials predominate in a government that includes factions close to Moscow.

The Angolan officials who did speak out, however, insisted that the United States can only risk further internationalizing southern Africa's conflicts -- and endangering its own standing throughout black Africa --by continuing its hostility to Luanda and focusing on the Cubans and Soviets, rather than the South Africans.

Since the most recent invasion of Angola by South African troops seeking the bases of the Namibian guerrilla group supported by Angola, the Southwest Africa People's Organization (SWAPO), the split between U.S. and Angolan leaders over Cuban and South African influence has grown sharper.

After the United States stood alone in vetoing a U.N. Security Council resolution condemning South Africa for the military action, an Angolan government statement accused the Reagan administration of "shameful connivance" with South Africa, an implication that a perceived U.S. shift toward Pretoria had encouraged it to launch the invasion.

In addition, do Moura last month called in the diplomatic corps to appeal for condemnation of South Africa. He compared the absence of Western comment with the publicity for "50 American criminals," his reference to the American hostages held in Iran.

For its part, the United States has increasingly talked about what it sees as a danger posed by the presence in Angola of about 15,000 Cuban troops and 1,000 Soviet military advisers.

The American pressure -- like the protests of Angola -- has had little apparent effect, however. A Western ambassador, one of a number who will speak to a reporter only with the understanding that he not be named, said that presenting the U.S. view in Luanda was "like pushing a pea up a hill with your nose."

In fact, Angolan officials now are hostile even to queries about the number of Cuban troops and the cost of maintaining them. "How many Americans are there at Guantanamo the American base in Cuba and what does it cost?" do Moura shot back in answer to that question.

Luis da Almeida, Angolan ambassador to France, came the closest to giving any information on the subject, saying there were fewer Cuban troops than five years ago, while refusing to say how many there were then.

"The United States is the last country in the world to give a morality lesson," he said, citing the presence of American troops "in South Korea, West Germany, all over."

"The U.S. should set the example of withdrawal and Angola will then have the Cubans leave," he said, a smile lighting his face at the idea.

Almeida, like other Angolans, was just as quick to express his annoyance over what he sees as the Reagan administration's penchant for regarding Angola as dominated by the Soviet Union.

"We were dominated for years by the Portuguese. We will never accept to be dominated again," he said. "You Americans cannot seem to realize that we can think with our own minds. Why must we always be pro-something?"

For the Marxist government in Angola, the crux of the problem with the United States has been just this kind of misperception through the last two turbulent decades of the country's history. Time and again, they would argue, Washington, absorbed in its own strategic interests, has backed the wrong side in Angola's struggles -- or at least, the side that lost -- at the expense of further eroding its position in the region.

The Cuban and South African issues are just the most recent focal points, by this account. Twenty years ago, when antigovernment guerrillas were battling Portugal's centuries-old colonial dictatorship, the United States supported Portugal, its ally in NATO.

Many of the weapons used by Portugal against the guerrillas during the long independence war came from the United States. A number can still be seen -- with prominent notations of their U.S. manufacture -- in the military museum in the old Portuguese fort overlooking Luanda.

When the United States finally decided in the 1970s, as the Portuguese government was collapsing, to hedge its bets in the liberation struggle, Washington chose to support the two factions that eventually lost, Jonas Savimbi's National Union for the Total Independence of Angola (UNITA), and another group led by Holden Roberto. Both were more tribal-oriented than their their ethnically diverse opponents.

The Soviets, meanwhile, had long backed the Marxist-oriented Popular Movement for the Liberation of Angola (MPLA), and eventually, Moscow's financing of Cuban troop involvement during the civil war that followed Portugal's departure proved decisive, helping to repel a South African thrust northward.

The South Africans finally had to withdraw when the U.S. Congress cut off its military aid to forces in Angola.

It is estimated that both the superpowers provided about $80 million in weapons, with much of the U.S. support being channeled through the Central Intelligence Agency. The CIA also funded European and American mercenaries.

The mercenary issue, in fact, carries over into U.S.-Angolan relations today. Two American mercenaries, Gary Acker and Gustavo Grillo, are still imprisoned in Angola, serving 30- and 16-year sentences, respectively, for their activities with the U.S.-backed groups. A third, Daniel Gearhardt, was executed in 1976.

Little is known about these prisoners. The Italian Embassy, which informally represents the United States on the prisoner issue, is able to check on their condition about once a year. A diplomat said that the Americans are faring as well as could be expected and that their condition is "normal."

Another American, Geoffrey Tyler, joined the two mercenaries in the castle-like Sao Paulo Prison in February after a small propeller plane he was ferrying to South Africa made an emergency landing in Angola, and Tyler's case is believed to have made the Angolan government suspicious. It represented at least the fourth incident of an American pilot making an emergency landing along the southern Angolan coast, not far from areas of guerrilla and South African military activity.

Despite all these tensions, Angola has not yet abandoned its outward efforts to improve relations with the United States -- perhaps because the continuing U.S. role as Angola's largest trading partner and likely broker of any Namibian settlement leaves the Luanda government little choice.

Last month, for example, the Angolans gave an amiable reception to a visiting U.S. congressional delegation led by Rep. Howard Wolpe (D-Mich.). The two-day visit was marked by an atmosphere of relaxed cordiality and numerous Angolan statements about building friendship between the two countries.

Warming to the subject of U.S.- Angolan relations in an interview, Almeida praised the American constitution, calling it "a poem."

"But you have such bad external polices," he said. "You support independence, but when people fight for it you are against it.

"You supported Portugal and now you support South Africa. If apartheid is 'repugnant' to President Reagan, why are you doing everything to support apartheid? It is contrary to your constitution."

At the same time, Almeida made a pitch for a U.S. diplomatic presence in Luanda. Quoting a French saying, he noted, "The absent are always wrong."