I agree with the 2nd answer.
He is also the figurehead of the right that the left has targeted to discredit and bring down the conservative part of the political spectrum. It is VERY important to the success of the liberals that the conservative administration be discredited so that they can gain control, and they will stop at absolutely nothing to get there. They have the bulk of the media backing the, too. Now, I am not saying that the Bush administration didn't give them plenty of ammo, but their assault on him has been unceasing, vicious, and a big part of it unwarranted. I'm sure that there are quite a few folks out there that don't really know why they hate him, they just do because everyone else in their group does.
Just look at some of the asinine responses above about him and you will see that they have proven my point themselves. It's one thing to disagree, even vehemently with someone's policy, and another to just insult them.
You have to understand that control of the US government, it's budget, armed forces, and the wealth and prestige that comes from that position are at stake.
Representation of the people is NOT at the top of the list.
The conservatives did the same thing during the Clinton years.
See what I mean. One of them called him a "Warlord and a warlock", proving my point even more.