Please don't call or even imply a user is dumb regardless on whether you feel they "deserve" it. How would you like it if someone did the same to you?
I'm going to start handing out for infractions more aggressively in this and similar threads.
Calling someone a horrible person is very much worse than calling someone dumb.
Also, there is a big difference between calling someone dumb and calling something someone said is dumb. A very intelligent person can say and think stupid things, and we have a thread to quote "ignorant" posts.
This I agree with, though comments resembling the latter are sometimes moderated on here anyway if they lead to threads being derailed or a poster is particularly aggressive in doing so or has a history of being agressive.