Sometimes they do think it's appropriate, like Bert's case. Though, not deliberately wanting to get banned, that case should at least warrant a couple month temp ban, as with Peter.
Bert, as Staff admitted, was a mistake and should have been banned.

So, maybe if the porn was in its own thread, that could mean permanent ban.
I don't see how that effects anything. What's next? Porn in GC being worse than porn in FF7?

I agree with all of this. Sometimes, a permanent ban just isn't warranted. Temporary bans have been used before, and have been effective.
I think the "drink tank" is effective. Other forms of temp-banning haven't been used in a while, but the "drink-tank" is definitely an effective form of temp-ban, and I think it should be used more. Maybe something similar?