Thousands of people cheered the former hostages' motorcade as it passed the District Building yesterday afternoon but, inside, Fred Watkins, a security guard and one-time infantry man in Vietnam, was less than impressed.

"If you want my opinion, this is just a bunch of stuff," he said "I was in 'Nam for 12 months and nobody gave me a parade."

At a bar in downtown Detroit one night last week 500 customers, most of them black, many of them unemployed, waited for a band to start its second set. "Let's hear one for the hostages," a band member shouted into the microphone, only to be greeted with loud and persistent boos.

On a Washington street earlier this week, a bank teller expressed anger, not at the released hostages but at the media that have been covering them. "It's getting on my nerves," he said. "Now that they're here I think they should be left alone."

They've received little attention in the press. Many are reluctant to voice their feelings publicly. Nonetheless, significant numbers of Americans want no part of national celebrations that began when the 52 ex-hostages flew out of Iran. Others followed the affair closely but feel the media are beating it to death.

The three television networks have given almost nonstop coverage to the homecoming. A reported 1,200 media people showed up in Weisbaden, West Germany, for the former hostages' stay there. For some viewers and newspaper readers this has raised fear the ex-hostages may have more trouble coping with kleig lights and reporters than they did with their Iranian captors.

But for other people wartime memories or political belief are behind their objections. Some of the nation's 2.6 million Vietnam veterans, for instance, have felt strongly conflicting emotions over the past week: relief that the captive Americans got their freedom but resentment that veterans, many of whom suffered far more physically and emotionally than the hostages, were often scorned or ignored when returning home.

Rocco Tedesco of Pleasant Hill, Calif., took part in search-and-destroy missions in Vietnam. Twelve years later, he says, he is not working because "I have a hard time getting along with people." That problem he blames partly on delayed stress caused by memories of combat.

Chris Johnson, president of Vietnam Veterans of South Dakota, lost a leg just below the knee in the war. Many vets in his state, he found after travels last week, feel anger building when TV coverage begins. It gets guys so disturbed that they can't even watch it."

Small things annoyed them -- the name of the jet that flew the hostages home, for instance. "They called it Freedom One. But every airplane that left Vietnam taking guys home was called a freedom bird." Still, these planes got no welcomes, he said. "The only thing we got was a new uniform and a burnt streak at the discharge station."

"You don't hear anything about the eight guys who died trying to rescue them," Johnson added.

Peter Tiffany, for 12 months a military policeman in South Vietnam, sees the nation's reaction as "a slap in the face. It's rubbing salt in our wounds." The hostages deserved the free services being offered them, he said but "not once since I got home has anyone sought me out to find out how I'm doing."

"You don't tell people you're a Vietnam veteran. If you do, you'll hear 'you lost your war, you're a baby killer,"' Tiffany said. He predicted the extensive media coverage of the hostages could trigger violent reactions in some veterans.

Many civil rights groups have issued statements hailing the hostages' release. But in some black communities there is feeling that the former hostages are a white concern and resentment that the country never mobilized with such intensity against discrimination or urban poverty. Such feelings seem to be behind displays of hostility such as the one in the Detroit bar last week.

The Rev. Jesse Jackson of the Chicago-based Operation Push said: "There's great concern [among blacks] over the hostages coming home. But there's also great concern over the hostages at home."

Eighty percent of all prisoners in U.S. prisons are black, commented Jackson, who suggests that the new media give this as close a look as the hostage affair has received. Another Push spokesman said some blacks feel they have all been held hostage for the last 300 years.

A black convict at a Maryland state prison laughed last week when a visitor asked if the radio had carried new word on the hostages. "When are they going to release some of the hostages in the U.S.?" he asked. Perhaps government leaders were pushing the issue to divert people's minds from more important things at home, he said.

In American leftist circles, a few groups such as the extremist Revolutionary Communist Party have openly endorsed the embassy takeover as a legitimate means of ending U.S. interference in Iran.

Other more moderate voices on the left oppose hostage-taking, but ask that the militants' anger be seen in the context of American support to the deposed shah's dictatorship. The Carter administration's fixation with the issue, they say, fostered an unhealthy mood of chauvinism and confrontation, it is also said.

Members of some left-liberal think tanks on Capitol Hill talked of organizing projects to inform legislators of the past U.S. role in Iran.But hostility toward Iranians was so strong on the Hill that the plans were abandoned. "Hostage-taking became the issue," recalled one researcher.

The Rev. Charles Kimball, a Harvard doctoral candidate who visited Iran three times during the crisis, expressed relief that the hostages were home safe, but suggested that "we have a radical inconsistency in our concern for human misery . . . . The 100,000 people who went through the torture chambers of Savak [the shah's secret police] -- somehow that doesn't matter to most Americans."

From the right comes other criticism. Rick Nowacki, for instance, a Maryland steam engineer who served three years in the Navy, believes that military hostages "ought to be brought before charges of dereliction of duty and surrendering a military installation when they had the means to resist."

If the embassy's Marine guards had used bullets rather than tear gas against the militants at the time of the seizure, classified documents could have been destroyed and the Iranian government would have been forced to intervene to protect the Americans, Nowacki said.

"They're not worthy of a warm welcome home," he said. Nowacki linked the quick surrender to a national loss of will to fight. The Soviet Union would not stand for the takeover of one of its embassies, he said.

Waco security guard LeRoy Stweart, a seven-year military veteran, felt the former hostages did not warrant such heavy media coverage. "It seems like that's all we see -- cut in on sports, cut in on programs. It doesn't make any sense." He added: "The boys who lost their lives trying to help them, they're just forgotten."