Frederic V. Malek, Ronald Reagan's nominee for the board of governors of the U.S. Postal Service, chose at his confirmation hearings to go the "limited, modified" contrition route, until he got a brisk discourse from two exercised Democratic senators on the eternal Watergate themes of right and wrong and responsibility.

Malek, exhibiting the blinkered ethics that characterized many of those Green Berets in gray flannel suits who ran Richard Nixon's White House, told a governmental affairs subcommittee that he, after all, had not been charged or prosecuted for his famous "responsiveness program."

Apparently, he thought this circumstance gave him license to be a little bit devious and a little bit defiant about his past and to picture himself as a victim of his environment, of the "strict authoritarian" atmosphere of the "zero defect" administration.

The words conjured up his crew-cut, scowling former boss, H.R. Haldeman, and could have stirred a certain sympathy. But as Carl Levin of Michigan and David H. Pryor of Arkansas reminded Malek, he had made a notable contribution to that atmosphere with his hair-raising memo of March 17, 1972.

By the time the pair got through with him, Malek was swearing that if Ronald Reagan or his present employer, J. Willard Marriott, asked him to write such a document, he would refuse and resign.

It had not been easy to get him to that point in redemption. At his first session March 12, Malek, gray-haired but boyish at 45, called his "responsiveness" memo "overblown" and a "mistake." He later downgraded it from a "program" to a "plan" and said it hadn't been implemented.

In his carefully carpentered opening statement, Malek attempted a lofty, dispassionate, reproachful tone about his handiwork. One sentence would have been a credit to the League of Women Voters:

"The responsiveness program was an effort orchestrated by the White House and amongst departmental appointees, where overzealous staff people might be encouraged to step dangerously close to the brink and even overstep the boundaries of legality and impropriety."

Malek told Levin that it had been "worded in such a way that could be misinterpreted."

That was too much for Levin, who has one of the Senate's sharpest minds. He said bitingly to Malek that his words were "subject to only one interpretation, and that is a cold-blooded, calculated effort to sell government favors to the highest bidder in the Nixon reelection campaign."

Sen. John C. Danforth of Missouri, one of the Republicans on the Governmental Affairs Committee, who is embarrassed and mystified by the appointment, told Malek that he thought the concept of government set forth by Malek was "just totally wrong." Malek obligingly replied that he now "fully deplores" it.

Levin erupted again. "You are acknowledging in the abstract that certain activities are wrong but essentially denying any wrongdoing on your part. Did you do anything wrong yourself?"

"What do you define as wrong, senator?" Malek rejoined coolly.

Levin said that while election year grants and appointments are not unheard of in politics, they had never been so blatantly detailed in a "confidential, for-eyes-only" White House memo, complete with deniability and an unparalleled range of punishments for the uncooperative.

The deputy chief counsel of the Watergate committee, James Hamilton, testified that the committee had rejected entirely Malek's "politics as usual" contention about the plan.

About Malek's competence no one had questions. A graduate of West Point and Harvard Business School, now a Marriott Corp. vice president who earns $335,000 annually and supervises 3,000 employes, he can make the trains run on time.

Nobody denies that the Postal Service could use a touch of "responsiveness" in moving the mail, or that Malek's capacity for firing people--he achieved a grisly celebrity status for his swift dispatch of Interior Secretary Walter Hickel's survivors, after Hickel himself was fired--could be put to good use amid the nine-number zip code set.

But the question that hung over both hearings and was several times spoken by Pryor was "why Malek?"

Pryor asked Malek how and when he had changed. Malek was unable to pinpoint the location of his Road to Damascus. He said something about having had "10 years to reflect."

But Pryor, having seen Malek's repentance set in only after he was challenged at his first hearing, seemed unconvinced. He mused that he was not certain that it was the "duty of Congress and the government to be a halfway house."

The vote on Malek is expected to be on strict party lines. The White House has no Watergate nerve; it is planning to send up Maurice Stans for appointment, too.

The answer to Pryor's question is quite simple. The Reagan White House doesn't know many people.