That so many young people who idealistically embraced him can't stand him now doesn't mean he changed, just that they woke up to who he really was all along.
Seriously, no surprises here. If you believed the impossible promises he made on the 2008 campaign trail, I'm sorry, but you were warned.
(Incidentally I intend to pay a lot of attention to the negative reporting done on candidates I support in the future, because it represents a worst-case scenario if the pundits actually turn out to be right)