WHEN U.S. CUSTOMS officials in Minneapolis found a copy of a homosexual-oriented magazine in the suitcase of a West German visitor last summer, they proceeded to grill him: was he a homosexual? "No, I'm bisexual," the man replied -- which was enough for Immigration and Naturalization Service inspectors to deny him entry into the country. At the San Francisco airport, a London man wearing a "Gay Pride" button got the same question; when he said he was a homosexual, he was told he could not enter the country.

Intolerant receptions, yes; but they were based on a policy Congress enacted 27 years ago. Then in August of this year, the surgeon general announced that homosexuality would no longer be considered by government physicians to be a "mental disease or defect." That led to the dropping of a Justice Department suit against the Londoner. But on the next day, immigration authorities in San Francisco stopped two men, one with a gold ring in his ear and another with what authorities said looked like a woman's handbag. Under a temporary INS policy, these two were conditionally admitted pending resolution of the issue.

Now comes a conclusion by Justice Department lawyers that INS must enforce the old statutory ban on the admission of homosexual foreigners. It is absurd. Sexual conduct, unless it is violent and criminal, should not be a criterion for judging who does and doesn't qualify to visit this country. The provision of the statue should be replaced.