Tuesday's Mary McGrory column incorrectly stated that the Justice Department had denied Hortensia Allende access to the United States earlier this year. The State Department denied a visa to the widow of slain chilean leader Salvador Allende.

Wouldn't it be wonderful if the U.S. officialdom and the public got as exercised about real scandals as they did over Interior Secretary James G. Watt's idiotic performance over the Fourth of July appearance of the Beach Boys on the Mall?

The president, the First Lady, the vice president and the White House deputy chief of staff all plunged in to heap indignation on Watt's head, and a major public relations offensive was launched to make sure that American citizens understood that their outrage was shared at the highest levels.

The secretary was sent out of the Oval Office to greet the public with a plaster cast of a foot with a hole in it to make the point that he had shot himself in the foot by his boneheaded slur of rock musicians. From the carrying on, you might have thought the Bill of Rights had been breached or some fundamental human right had been trampled into the ground.

Rock fans were, of course, incensed that this country has anyone in charge who doesn't know the difference between heavy metal and the mellowed-out Beach Boys. Other Americans, who share his ignorance, were affronted by Watt's designation of his choice of substitute talent, Wayne Newton, as "typically American."

If Newton has become the standard of family wholesomeness, which is the note Watt wishes to introduce on the Mall, our measurement of the "traditional values" may require some revision. A flashy entertainer in wide lapels, he surrounds himself for his big patriotic numbers with sexy Vegas women, at whom he leers and to whom he addresses suggestive remarks of the type that most mums and dads feel make him something less than a role-model for their teen-age children.

Apparently, Watt thought he was scoring something of a coup by acquiring an entertainer of American Indian background, which Newton is, to lead the celebration of our national holiday. It is possible, of course, that Indians might appreciate more a little more day-in, day-out consideration from the secretary of the interior--who has called their reservations an example of the failure of socialism.

The Beach Boys, however, have more defenders in Washington than have the Indians. Several members of the House took the floor to make sport of the secretary's presumptions, knowing that it is far easier to stir a frenzy over a show-biz slander than over his attempts to cancel national parks and wilderness areas.

The president made much of the fact to a group of visiting educators that it was a pleasure "to break away from crisis negotiations." By making a national joke of the whole thing, he deflected attention from his unwavering adherence to a Cabinet officer who makes a career of alienating large segments of the public on far more important issues.

A month ago, another Cabinet officer, Attorney General William French Smith, effected an egregious cancellation of an appearance by a public figure, one that was far worse and far more "un-American" than Watt's folly. It went by without a ripple.

It wasn't a show biz personality that was involved. It was Hortensia Allende, widow of the assassinated Marxist president of Chile. The U.S. contribution to her widowhood is not clear, but the machinations of the CIA to prevent her husband's access to power have been documented in hearings of a Senate select committee.

The auspices under which she had been invited were respectable. Her hosts were to have been the Roman Catholic diocese of San Francisco. But the attorney general ruled that her address on women's and human rights issues "would be prejudicial to U.S. interests."

Little attention was paid to this manifestation of paranoia in the administration. You would think that it was a shaming thing that the greatest democracy on earth felt menaced by a speech by a 66-year-old woman who understandably does not share President Reagan's enthusiasm for the present Chilean government, which killed her husband and oppresses her countrymen.

And, while the air is still ringing with denunciations of an out-of-it Cabinet officer, we could reflect on the immunity enveloping those officials who are masterminding the overthrow of the government of Nicaragua. No one has stood up to demand an accounting from CIA Director William J. Casey, Secretary of Defense Caspar W. Weinberger and Secretary of State George P. Shultz, all of whom presumably are involved in the plot against the Sandinista regime.

A couple of senators have murmured that they are "deeply worried," but there is no outcry even remotely on the Beach Boys' scale. The administration could be breaking the law: Congress forbade it to engage in military activities aimed at the overthrow of the Nicaraguan government.

But not to worry. No show-biz celebrities are being wounded.