I think at least some of it has to do with underlying racism in our country, along with the large divide in the US regarding political ideologies.
Bush had some folksy charm but he generally came off as a moron whenever he opened his mouth publicly AND put our country trillions of dollars into debt after Clinton had put 8 years in digging us out of the debt hole. Bush sr. might have done an OK job as president, but G.W. certainly did not.It's basically an internet thing. The only reason Bush and Obama are "seen" as bad presidents by the internet is because pre-Bush, we barely had the internet.