Yes, I held my nose and voted for him in 2004. And I voted as near Republican as I could in 2006.
Bush's unnecessary spending, his failure to prosecute criminal Democrats, his failure to clean out Foggy Bottom, his love of Mexico over the US, his deals with Saudi Arabia, his failure to let the military win the war, etc., adds up to a massive amount of disillusionment that overwhelmed many ungrounded voters.
There are many other Bush failures too. People can't see a dime's worth of difference between Whorhay and Dems in charge.
Bush has not been a very good president, for basically the reasons you cite. But a Rat would be an utter disaster, and that's much more than a dime's worth of difference.