Most people just dont know about his history and his social positions. There are varyign levels of political knowledge. People like us freepers are probably know the most about the candidates and as such we know rudy's record, your average person involved in GOP activites knows a lot more than your average joe but not that detailed into the candidates like freepers.
I.e. When i went to various state gop functions and poked and ask around, less than a quarter of the people there really knew anything about rudy's liberalism. You'll see rudy supporters tout, oh but look how well he did, these people aren't as aware as most people think they are though.