It may be a fine distinction, but I do not see PZ's impoliteness and insults as directed at the Catholic faithful who believe that God is present in the communion wafers, however much PZ would disagree and consider them to be naive and/or deluded and/or misguided. Rather he is (verbally, of course) attacking those who think it is appropriate, or even understandable, to respond to blasphemy and sacrilege with physical force and death threats.
Here is a letter I sent to the President of UMM:
Dear Dr. Bruininks,
I firmly believe that, in addition to transmitting knowledge on various topics, one of the important roles of a university is to encourage students to think critically and question their own and their world's basic assumptions. I think that Professor P.Z.Myers does an excellent job in all of these areas, and is a credit to UMM.
Recently, I have seen blog posts by Dr Myers in which he has encouraged desecration of Catholic religious symbols. Bill Donohue has stated that "It is hard to think of anything more vile...". While the comments and proposed actions by P.Z. Myers may be insulting and impolite, surely there are many things in this world far viler than denigrating symbols and beliefs.
I hope you will disregard the demands from the Catholic League for the removal or other discipline of Professor Myers, and support his right to voice his opinions, however controversial they might be.