Like lots of Washington visitors, Joe Modero and Anthony Rubino came here yesterday because this is the nation's capital, home of the president and the place where Congress dwells.

Like lots of visitors, the two were dressed casually, and were a little low on money. Like others, they found Washington pretty, but confusing. And like others they mistook the back of the White House for the front, the way it seems in movies and on postcards.

Unlike most tourists, Modero and Rubino brought 1,988 friends with them. They came to yell at the president (with a permit), yell at Congress (with a permit) and demand jobs they lost last year for striking against the U.S. government.

Rubino, Modero and others wonder why D.C. teachers don't get fired for striking, why air traffic controllers don't get fired, and yet why they got fired. Some think the major mistake was that the strike wasn't big enough.

The two were among about 200 employes fired last year. They allegedly participated in strikes at postal facilities in New Jersey and California. They protested a "lousy" contract between their unions and the U.S. Postal Service.

Strike leaders claim that more than 5,000 people struck, yet only a handful punished. One man said he was a union shop steward. "The postal service went after people it wanted. I gave them a lot of hell on the contract." Postal officials say the employes violated the law that requires strikers to be fired, fined or jailed for "withholding labor" from Uncle Sam.

Modero and Rubino say they are drawing unemployment about $110 per week) that is about to run out. They say they cannot get other government jobs, ever again. They were part of a 5-bus caravan of New York and New Jersey workers, friends and fired employes here to demand amnesty.

The group tried to see President Carter but got, as one put it, "a thirdstringer." She accepted their petition, outside the White House. Moe Biller, leader of the Manhattan-Bronx local, biggest in the American Postal Workers Union, then took the caravan to Capital Hill where they got sympathy if not results.

Most of the APWU's national leaders were elsewhere during the demonstration. Many were denounced in the same unflattering terms as Jimmy Carter, Postmaster William F. Bolger and "the media," which took its lumps for "siding" with management on the strike issue.

If the White House scene was confusing and frustrating to the employes, the skids had to have been greased on Capitol Hill. It was an all New York and New Jersey show. Even the Navy band, which had been scheduled to give a concert on the Senate steps, was bumped by politicians who preferred the noise of the crowd to the sound of music.

Sen. Jacob Javits (R-N.Y.) said he hoped "justice would be tempered with mercy" in the case of the fired workers. Rep. Mario Biaggi, a herocop who now represents the Bronx and North Queens, suggested that the postmaster general's decision might not be final. Rep. Lester Wolff of Nassau County said a government that could give amnesty "to people who fought against it, to people who wouldn't fight for it" could also be merciful to "dedicated employes" who had served it.

Vincent Sombrotto, head of a sister rival union-the Letter Carriers-spoke in support of the strikers. He's also a New Yorker.

Ben Zemsky and Kenny Leiner, the only APWU national officers at the rally spoke. Leiner is also a fired worker.

Zemsky said he hoped this would be the last rally for amnesty. He said "other action" might be necessary unless the strikers are rehired. He predicted the next contract (not due until 1981) won't be ratified if the amnesty issue isn't settled.

"We might have to shut it down, Zemsky said. "Next time," he said, workers might have to go to L'Enfant Plaza (USPS headquarters) "and tell them to get the hell out and we'll take over."

Nobody is sure what effect, if any, the rally will have on amnesty or future labor conditions for the 650,000 postal workers. Modero and Rubino said they didn't know. Both exmailmen got back on the bus. They said they will be looking for a letter.