Public television stations are not unlike commercial stations in the reverence they hold for innocuous hits. It's what they really want--imported costume dramas, or jerkwater frivolities like "Sneak Previews"rather than troublesome, talked-about blockbusters like "Middletown," the recently completed series of documentary films. Tonight at 10 on channels 26 and 32, PBS gives that irritating Ben Wattenberg a chance to discredit "Middletown," or at least make it seem boring, but he fails to do either.

"Middletown Revisited" was produced by WIPB in Muncie, Ind., the city that was the subject of the Robert and Helen Lynd sociological studies in the '20s and '30s as well as the recent six-part film series, of which only five parts were finally broadcast (the sixth, "Seventeen," fell victim to bureaucratic cowardice and klutziness).

Political adviser and public TV gadfly Wattenberg interviews various people involved, including sociologist Theodore Kaplow, who did his own "Middletown" studies in 1976; Peter Davis, executive producer of the film series; Tom Cohen, who directed two of the best "Middletown" films, "Family Business" and "The Campaign"; Muncie Mayor Alan K. Wilson and roguish entrepreneur Howie Snider, the patriarchal pizza maker of "Family Business."

The theory Wattenberg expounds, obsessively, is that Muncie, thus Middletown, thus Middle America, has stayed the same over the past four or five decades more than it has changed. He wonders, at the conclusion of this sloppily produced hour, why nobody makes films about things that stay the same. He might as well wonder why Dan Rather fails to report on all the airplanes that complete successful flights each day, or hopscotch the world looking for wistful vistas where nothing occurred.

Interviews on the program seem to have been edited to highlight sentiments that support Wattenberg's view. More than one interviewee is chopped off in mid-thought or mid-sentence. Wattenberg fuddles around with his pet line of inquiry, the result being that he proves himself correct in his churlish assertions. One wonders why the Corporation for Public Broadcasting feels duty-bound to support this sort of mission with money better used elsewhere.

To the Muncie Chamber of Commerce president and a local businessman, Wattenberg says, in response to the "Family Business" film, "I guess the first logical question is, 'Is Muncie a town of pizza parlors?' " That's the first logical question? "Middletown Revisited" documents nothing quite so well as Ben Wattenberg's insistence on missing the point. At this dubious endeavor, he succeeds all too well.