"I wouldn't go," said my brother. "It's a gay hangout." I later got a similar warning when I asked about Key West. Politically, both of them are more liberal than I so their opinions are not a "conservative" thing. I visit the Keys fairly frequently. I'm not a big fan of Key West for other reasons, but it's not that bad, certainly nothing like Castro Street. You have a few stores that obviously cater to a gay clientele, and a few very odd looking people on the street, but mostly it's a hard-drinking, touristy kind of place. And some of the historical monuments are well worth visiting.
We wound up visiting Key West anyway and it was generally a fun time. But we didn't go to the beach. Since we travelled with my macaw, it was nice that so many businesses were accepting and accomodating to parrots.