Personal abuse has nothing to do with this issue.
So personal abuse does limit freedom of speech?
I am convinced that the christian gospel is psychologically harmful.
What all of it? Every single element? Every doctrine?
Is there not a difference between statements/doctrines that aren't harmful (God is three persons in one) and statements that are harmful (Gays can change).
One has almost no possibility of being harmful.
The other does.
This is why that video has so may dislikes.
You seem to be taking an all or nothing approach. I would suggest that's pretty extreme. If a statement of belief is harmful (Gays can change) then yes if should be banned.
Think whatever you want - but that doesn't mean you're free to state it. That applies to religious statements as much as racist statements.