For "flaming" and "trolling", I think that moderators should only moderate "extreme" comments (which itself is vague).
The main problem with trying to moderate "offensive" language or "trolling" is that there's no clear standard and it becomes arbitrary. Try to implement rules, it becomes confusing and just impedes discussion.
As much as I hate fanboys, I hate the fucking PC bullshit that goes on here. Again, one, it's inconsistent, just by the subjective nature of "flaming" and "offensive". Anyone can feel like they're being provoked or offended. Two, it just kills off any critical opinions, or in the OP's case, any jokes.
While "extreme" is subjective, I'll rather take the inconsistencies with moderating "extreme" stuff, than with trying to fuck around with the huge possible range of "flaming", "trolling", "prejudice" comments.