Public television operates according to a churlish Calvinism. We are permitted little blips of pleasure here and there, but how we must suffer for them! There are about 15 priceless minutes with "Musical Comedy Tonight," the PBS special at 8 tonight on Channel 26, but they are camouflaged within an hour and a half of hype-hype hooray and showbiz gush.

Sylvia Fine Kaye (Mrs. Danny Kaye) put together this tribute to the musical theater, which features numbers from four classics, major and minor: "Good News," "Anything Goes," "Oklahoma!" and "Company." The goal is commendable enough, but the program comes afflicted with laugh-track fever and a slavish homage to the star syndrome.

Though we zoom in on a shot of New York's Schubert Theater at the opening, the program was taped at the Wilshire Ebell Theater in Los Angeles, where the invited audience applauds so excessively and so readily you'd think their little mitts were freezing. Maybe the air conditioning was turned up too high.

When their toadyish enthusiasm wavers, electronic "sweetening" is there to cover tape edits and brighten the audio into a state of coma. Why haven't PBS officials laid down the law against the use of fake audience response in public television? Because they don't realize that canned reaction is one of the things people flee commercial television to escape?

As an overview of the musical comedy, the show lacks breadth. Goerge and Ira Gershwin and Jerome Kern are mentioned, but their music is never quoted. If the idea was to summon up only turning points, "Good News" is conspicuous by its presence and "On Your Toes," "Show Boat" and "Of Thee I Sing" by their absence.

The presence of old iron lungs, Ethel Merman, is of course an authenticating one, though her tempos drag on "I Get a Kick Out of You" and "You're the Top." For the latter she is teamed with a leaden Rock Hudson, who typifies the Hollywoodness of what should have been a New York production. The use of such performers as Richard Chamberlin, Sandy Duncan, the singing newt John Davidson and even Carol Burnett indicates sloppy priorities.

How much better to have recruited less luminous names from the rash of recent Broadway revivals of the good old shows. We don't want a public television that is star-studded. We want a public television tipsy with talent.

The highlight of the program is an appearance by the probably miraculous Agnes de Mille, who explains her choreography of the "Out of My Dreams" ballet from "Oklahoma!" as it is danced by the callously unbilled Gemze de Lappe, who played the same role in the post-War British production of the show.

De Mille chats with host-producer Kaye about the New York run, when she'd see American servicemen three-deep at the back of the theater before they left for Europe, "tears streaming down their cheeks" over this sunny show, because to them "it symbolized home, and what they were going to die for."

As a host, Kaye clings to cue cards with distracting fidelity. Her commentary is bright and judicious (except when trying to make a connection between Stephen Sondheim's "Company" and the Vietnam war), and her every stab at wit rewarded with either real or test-tube laughter from the crowd or an electronic pushover. Stan Harris's direction is lazy and camera placement unimaginative.

Public television could be a medium of record. The musical theater is dead now, but old shows are constantly being revived. These should be committed to tape now so they can be enjoyed by millions and preserved for the future. Humdrum samplers like Kaye's may sound like hot box office to PBS executives, but they can only prove frustrating inadequate in the long run. This project deserves a short one.