SAN FRANCISCO, May 11, 1998 - I'll be watching Thursday night, applauding Seinfeld's stellar run. And I'd never want to rain on his parade. However, my comments will hardly constitute a drizzle. So let me go ahead and mention the parade, the Puerto Rican Day parade around which the show's second to last episode revolved.

Predictable indignation among Puerto Ricans after the show aired, just as predictably prompted shrugs and rolling of eyes from everyone else. Few could see the umbrage taken by Puerto Ricans as anything else than a knee-jerk reaction by an overly sensitive minority that can't take a joke.

There's a bit more to it than that.

Consider: "Seinfeld," television's highest rated gold mine, will depart Thursday night with enough people watching for a commercial during the farewell episode to command astronomical fees equivalent to that of a half-time spot during the Super Bowl. The hyperbolic count down has had the nation similarly glued to the tube.

Now here comes the second to last show, the penultimate half hour. And there's Jerry stuck in traffic in the middle of the Puerto Rican Day parade. Beautiful. Possibly the only aspect of the Puerto Rican people that hasn't been exploited by this country is the extraordinary humor of their situation. Surely, "Seinfeld" will have a field day, I thought, and sat back for some quality laughs.

Instead, the script resorted to cheap laughs, and not many at that. Agonizingly below the standards of comedy writing that made the show a success, this episode took the easy way out and fell flat. In the shallowest of caricatures and deathly stale gags, Puerto Ricans were depicted as loud, grease-headed, criminally prone hot heads with what sounded like poorly approximated Italian accents.

O.K. we're loud. Sure, a bit hot headed. And if you happen to set the Puerto Rican flag on fire during the parade, as Kramer did in this episode, your life may very well have been in jeopardy. However the treatment of the situation was low grade. Not only did it entrench unfortunate stereotypes, I've heard better lines written for Eddie, the canine foil on ''Frasier.''

For the first time I was truly disappointed in Jerry Seinfeld, a man whose exceptional work on stage I've admired ever since first catching his stand up act at the original Caroline's Comedy Club on Eighth Avenue in New York City long before he ever had a television show. Yet there I sat, last Thursday night, grudgingly muttering, ''I can’t believe it, Seinfeld, a hack."

Certainly the episode suffered for the fumble of a great opportunity for humor. But it didn't suffer for it nearly as much as the Puerto Ricans. When you are depicted so rarely in mass media, each one of those occasions matters that much more. When a show the kind of exposure that "Seinfeld" delivers, delivers nothing but a regurgitated, unflattering image of your people, it's hard to swallow benignly.

Note that in the episode previous to this one, the plot involved Seinfeld becoming indignant when a friend of his converts to Judaism. Jerry concludes, incensed, that his friend has converted only to enjoy the privileges of Jewish humor. "He's in it just for the jokes!" Jerry wails, quite offended that his proud heritage should be appropriated on such a superficial basis.

Then the following week, in front of the eyes of millions of viewers, Puerto Ricans are used merely as the butt of some lazily constructed lowest-common-denominator cracks. And we had no opportunity on the show to utter a retort, humorous otherwise, in our defense.

Puerto Rico marks 100 years under American colonial rule this year. While Israel celebrates its 50th anniversary as an American-backed independent state.

And it's precisely the kind of persistent American indifference toward Puerto Ricans, exemplified by their lamentable cameo in Seinfeld's series, that stands as one of the main hurdles to improving their social stagnation, both on the island and the mainland.

America is a country where image rules in an age where image has never been more instantaneously malleable. The mass-media image of Puerto Ricans hasn't been updated since we last saw Natalie Wood screaming, "Chino! Come get me Chino!" in "West Side Story."

Doubtless its time to update that image. And no, it's not up to Jerry Seinfeld. It's up to us to define our own image, to represent Puerto Ricans with full respect for, and in full context of, who we are in three, pander-free, dimensions.

Its time we delivered our own television show about us for prime time. I'll personally take up the challenge.

Meantime, it is important to understand this. Although, the “Seinfeld” show may claim to be a show “about nothing,” the clamor that rose from the Puerto Rican community over their careless depiction in such a television phenomenon, during its widely watched home stretch, was not.