Hiding sexuality is just another way of apologising for it. Anybody who's ever enjoyed sex which isn't strictly missionary knows that the over-riding sensation isn't regret. Deviant sexuality isn't 'harmless'. We stop following the straight and narrow and start making our lives up as we go along. It's the fact that we've started to play instead of playing by the rules.
Queer culture looks fun and that sticks in the homophobe's gullet.
They want to pretend that we're sad, sick little bastards with no lives - anything other would throw 2000 years of tradition into question. Homophobes swear by tradition. The order of gay nuns, the Sisters of Perpetual Indulgence, are the homophobes' worst nightmare. If there's a problem - it's yours. Their upfront gay pride makes a mockery of the paralysing guilt which stops us from exploring and expressing sexuality.