When the New Jersey State Commission of Investigation recommended recently that professional boxing be outlawed in the state, the reactions from dedicated sportsmen were clangorous and predictable.

A boxing promoter warned that if such an un- American law were passed, boxing would be driven underground "where there are no controls." Another promoter hotly denied the commission's charge that this sport of gladiators is infested with "wise guys," as some police detectives call members of that corporation which the governor of New York claims does not exist.

But the State Commission of Investigation had also claimed that its two-year investigation of what it calls "legal savagery" verified earlier reports by the American Medical Association and other medical groups that "too many boxers retire as physical or mental derelicts." It figures. Anyone who takes hundreds, thousands, of blows to the head in the course of his work has a good chance of going fuzzy into that good night.

The answer to this grim prognosis from boxing fans I know is that "the sweet science" is the only way up out of the streets for a lot of kids from the wrong side of the tracks. Only effete patricians with money of their own would try to deny these brave lads from the underclass an opportunity to make something of themselves. There may be some risks, but that's the American way.

Friends of mine who were the first on their block to join the nuclear freeze movement, and who still play old Joan Baez records, are also infuriated by the self-righteous arrogance of any government body that would interfere with private pleasures. As proof that decent Americans can approve of boxing, they cite Red Smith. He was indeed the most civilized of all writers on sports, and his prose was as clear and crisp as Doc Cheatham's trumpet. It is true that Red Smith believed boxing "at its best" is "one of the purest of art forms."

Red Smith also said he understood some people sincerely felt boxing had no place in a civilized society. Well, he went on, there have always been "men ready to fight for prizes" and "it is hard to believe that a nation bereft of such men would be the stronger or the better for it." In the ring, Smith emphasized, the professionals "accept the stern code which demands that a beaten man go on fighting so long as he is able to stay on his feet."

For nine years, I watched, at ringside, hundreds of young and not so young men follow that stern code. One of my assignments at a Boston radio station was announcing the fights. Sometimes between-rounds color; sometimes the blow-by-blow report to aficionados throughout New England.

The first thing I learned in that job was not to speak to certain people in the dressing rooms unless I was spoken to first. And I never was. They were men in dark suits with closed faces, and they owned the most promising fighters. Some of them I also saw backstage in nightclubs where I did band remotes. They owned people there too. Once I saw who owned them when several knelt and kissed the hand of a glacial visitor from Providence. He was not a member of the clergy.

In the ring at Boston Garden, week after week, men tried to beat each other unconscious and often succeeded. The fans were far less interested in boxing than they were in clubbing. They did pause to admire the precise grace of a Willie Pep, provided there had been enough blood in the preliminaries. But seeing a man stretched out senseless made their night. And if a badly hurt fighter, still on his feet, kept trying to hold on, the mob -- the ones in the seats -- often started throwing things. The sissy was defiling the sport.

I particularly followed two club fighters over the years. One was a red-headed Irish kid, the other a swarthy Italian. Just like in the old B movies. The first few years, both had prospects. They were fast, hit hard and could take a lot of punishment. They were unfailingly faithful to Red Smith's "stern code."

They made it into some main bouts, occasionally against each other, but they never did make it to Madison Square Garden. The Italian kid, who was no longer a kid, became punchy, but even so he kept being led into the ring like a moth-eaten bear staked out to be baited by dogs. The Irish fighter just wore out. When they were through, neither had any money left. Nor do most of the survivors, punchy or not. The managers and the wise guys do okay.

As for the warning that making this sport illegal will drive it underground and beyond controls, Dr. George D. Lundberg of the AMA says it's like arguing that "gunfighters' duels should be instituted, tickets sold and betting promoted since, after all, homicide by gunshot is also common in our society."