He very well could have correctly said “Being homosexual is not a sin”.

Because it isn’t.

What my religion frowns on is sex outside of marriage - whether homosexual or heterosexual. Both are sinful.

But the mere fact that one is homosexual is not in any way a sin.

And besides which, we don’t play God and judge the extent of sinfulness of others.

We know what is legal or illegal, and judge that. But final judgment on the sinfulness (or lack of) in others is not our job.