[user104658]

Homosexuality IS a sin in most religions, there's not really any two ways about that, it's stated explicitly in most religious teachings.

However, the concept of "sin" is bull****, so the fact that it's technically a sin should be considered to be completely irrelevant to any discussion in the modern world, and most importantly in politics.

Having looked into this, though, he's not just saying that homosexuality is "technically a sin" - he's saying that he personally believes it and considers homosexuality to be "wrong". Which is obviously much worse than just pointing out that the "bible sez" it's a sin.