Why are most religions agains homosexuality?

[Wyrd of Gawd]

Because those books were written by primitive fuckwits.

They also probably liked each other's cocks but they were in denial about it. All 3 of the Abrahamic religions probably came out of a repressed rage.

They certainly were fascinated by penises.  There's a funny story in the Bible about Paul circumcising Timothy.  The practice seems to have been that when a strange man went to a Jewish gathering for the first time he had to whip out his circumcised dick to show that he was a member of the clique.  And don't forget when Abraham's servant swore an oath by cupping Abraham's testicles in his hand.  That's where the word "testimony" comes from.