It's because when the religions arose, people wanted civilisations to expand. Homoesexuality and masturbation don't increase population, so were discouraged.
@GlassDog A lot of the Greek and Roman pagan religiouns promoted a hedonistic lifestyle with male and female children, often of the same sex. That was the time and area most of the Christian verses that condemn it were written. I think much of it had to do with that.
@JustGoneNow That's a good point. I didn't think about pederasty. Although are we judging that as wrong based on our modern perspective (which we now think it clearly is wrong)? It's difficult to know what people would have thought back then particularly when men would have taken wives as young as the catamites.
@GlassDog Paul primarily, appeared to have issues with women and sexuality in general. It bears mentioning that the writers of the Bible were human men, with conceivably their own hangups.
