SOME FRIENDS of Dyke Marsh are complaining because the wildlife sanctuary, south of Alexandria, has become a popular place for homosexual liaisons. So the obvious jokes have proliferated. Only it's really not very funny for park visitors -- kids included -- who witness the activity or for National Park Service officials, who would like to curb such gatherings there and elsewhere along the George Washington Parkway but who don't want to be charged with harassing citizens who happen to be gay.

Engaging in sexual activity in a public park, however -- whether it is heterosexual or homosexual activity -- can hardly be considered an exercise of First Amendment rights or personal freedom or civil liberties or any of the rest of those grand ideas. It is an affront to and an intrusion on others. And these sex-in-the-park gathering places are also the scene of much danger, inviting the attention of a variety of harassers, marauders, voyeurs and just plain sadists. In such a place, near the Iwo Jima Memorial a couple of years ago, the brutal murder of Ronald Pettine occurred. Taken together, the potential for violence and the reluctance of the victims to call the police when they can, amount to a prescription for terror.

The Park Service's job is to keep the parks available and acceptable to everyone. This does not mean keeping some people out because they may be homosexual. It does mean putting an end to the takeover of certain sections of the parks for sex festivals.Perhaps some parts of the marsh ought to be reserved for wildlife, with all people kept out; but that doesn't deal with the more exotic and outrageous problem with humans. Surely the Park Police and rangers should be much more visible and attentive all along the George Washington Parkway and nearby trails. Plainclothes work (Word Illegible) the police to arrest more offenders. The presence of uniformed officers or even rangers would do more to reassure the majority of park visitors and remind those who need reminding that sex in the parks is strictly for the birds.