I'm guessing a few think that while he wasn't trying something nefarious to gain an unfair advantage (like oversigning?) that there was still negligence going on in his program. Even if it's some bureaucrats in the AD who were supposed to keep track of this stuff so coaches can focus on the actual game, the leaders have to take responsibility. This should include other AD officials too, right? Of course since Rodriguez is under other pressure, he is singled out.
Also, some of us are swayed a little by public opinion. I am a little too, honestly. It's just something subconscious when you constantly see nothing but negative press for the man. Not that I think it has a good foundation, mind you. I'm still definitely in the camp that would give him until 2011, just occasionally feel overwhelmed by this junk.