It's best just to try and ignore threads like that. I've noticed and I've commented on it before, but you will never get a "now I think of it, that IS quite a waste of time and energy". What you WILL get is "if you don't like it, don't read it!"

Ya gotta think, if that kind of thing really does piss them off, what else can you do but laugh (whether is from amusement or pity).