Yesterday the Federal Communications Commission (FCC) proved it does know something about obscenity after all. It committed one. The Fairness Doctrine, which has operated to the salutary and statutory benefit of American broadcasting and its audience for 38 years, was thrown out by the commission in a gesture of colossally arrogant gall.

Four commissioners, as if beset by some exotic ideological influenza, decided the doctrine was "unconstitutional" even though the Supreme Court has previously ruled otherwise and a majority of the Congress has expressed its support for the doctrine. The rule requires TV and radio stations to give balanced treatment to controversial issues; the FCC says that is simply too great a burden for broadcasters to bear.

"I knew those lickspittles down there would do something like this," said Rep. John Dingell (D-Mich.), chairman of the House Energy and Commerce Committee. "Where this FCC is concerned, I am never surprised as to substance, procedure or timing." Dingell and Ernest Hollings (D-S.C.), chairman of the Senate Commerce Committee, are expected to attempt to get the doctrine reinstated by attaching it to legislation President Reagan can't veto when they return in September from their upcoming recess.

Dingell said the FCC is acting "at very substantial peril" and termed the decision, among other things, "a plain and simple outrage" and "a craven attempt to curry favor with a group that doesn't need help over an issue that doesn't exist."

With its repeal of the doctrine, the FCC abdicates another of its mandates to safeguard the public interest. This decision is not a free speech decision. It is a bought-and-paid-for speech decision. It aims to protect broadcasting companies still further from the public they are supposed to serve.

"They did the dirty deed," lamented consumer activist Ralph Nader yesterday after returning from the FCC's briefing. "The ghost of Goebbels would be chuckling. They totally ignored the First Amendment rights of the audience who owns the airwaves, airwaves that are only leased by broadcasters.

"Broadcasters already had an exclusive license. Now they have the exclusive power to shut out the audience altogether," Nader said. He called the commissioners "a bunch of lightweights like I've never seen before."

Nader said rules relating to the Fairness Doctrine -- like the personal attack rule that gives the victim of a broadcast broadside the right to respond, and the equal time provision, which requires stations to treat candidates in an election equitably -- are also doomed if the commission continues on its present nutty course.

On Capitol Hill, legislators were furious at what was seen as a foolhardy attempt at an "end run" around Congress, which earlier this summer attempted to codify the Fairness Doctrine. The effort was shot down by presidential veto. The FCC was created as an independent agency that reports to Congress, but now it is clearly acting as an agent of the White House.

Of all the potential calamities visited on the republic by the Reagan administration, the fumblings and bumblings of its FCC -- first under Chairman Mark Fowler and now under the equally misguided Dennis Patrick -- will get special chapters in history books.

Why trash the Fairness Doctrine now? The FCC claims the doctrine was initiated when there was a scarcity of broadcast outlets and that this no longer exists. That's gibberish; scarcity still exists, and the record selling prices for TV stations prove it. The concentration of media ownership is greater than at any time in American history, so the larger number of TV and radio stations is offset by the relatively smaller number of owners.

There is also the specious claim by supporters of the repeal that the doctrine has had a "chilling effect" on broadcasters, inhibiting them from tackling controversial issues. No such effect has ever been proven. The issue is bogus. Nader finds it laughable.

"A chilling effect? Well then," he says, "the next few months should see an absolute explosion of Athenian creativity and daring on radio and television -- now that the yoke of the Fairness Doctrine has been lifted by the 20th-century Minutemen of Ronald Reagan."

The chilling effect is the deregulators' Big Lie. Joseph Saitta, who has been in broadcast journalism for 21 years -- the last six months as news director of WTTG-TV here -- was asked yesterday if he has ever in his career felt any constraint from the Fairness Doctrine. "No, not that I can recall," he said. "I can't think of an instance where it's impacted negatively."

Lawrence K. Grossman, president of NBC News, was asked the same question. While Grossman feels the Fairness Doctrine to be "a bad doctrine in theory," he had to concede, "The answer, as far as I am concerned, is no, not really. The direct and honest answer to the question is no."

Andrew Jay Schwartzman, director of the Media Access Project, says the Reagan FCC's problem is that "they just will not recognize who's serving whom" and that "they just don't care" about "the public interest, convenience and necessity" that the commission was established to oversee.

"This decision is the embodiment of the FCC turning the asylum over to the lunatics," Schwartzman said.

Legislators and their staffs are so incensed about what they see as a "double-cross" by the FCC, that there is talk of immediate retaliation, like, perhaps, eliminating the commission's travel budget.

"I say, let them keep the travel budget. Just insist that all tickets be one-way," said Schwartzman. He was cheered by a vision of an FCC commissioner being stranded in Las Vegas after journeying there to make a speech for throngs of grateful broadcasters.

Somewhere along the line, the FCC completely reversed the roles of broadcaster and public so that the public is now deemed the servant of the broadcaster. The FCC has taken us through the looking glass. We have entered the flip-flop world on the other side. "Orwellian" is an overused adjective, but when dealing with the FCC, there is no way to avoid it.