As most "is... evil" threads make the assumption that it IS, then I'd say they are bad, as they in that case are judgmental.
(I can't remember a such thread where the thread starter later said "oh, btw, I think .... is OK". )
Also, some of the problem is that people seem to make some things SO much worse than others.
i.e: some say if you are gay you go to hell, some say if you commit suicide you go to hell. what they forget is:
But I tell you that anyone who is angry with his brother will be subject to judgment. Again, anyone who says to his brother, 'Raca,' is answerable to the Sanhedrin. But anyone who says, 'You fool!' will be in danger of the fire of hell.
I am willing to guess that most of us at some point said that to someone....
also, these threads seem to forget that God forgives those who repent. After all, if He didn't, what would be the point of Jesus?