I would guess you are too young to remember the presidents who preceded him. It wouldn't be such a puzzle to you if you did.
Yeah, I was in pre-school when Reagan was elected. I remember my parents were very excited because they were very dissatisfied with Carter. Having subsequently learned about Carter and previous presidents in history class, I know they had good reason to be.
I suppose it is human nature to put a good man, who changed a lot for the better, up on a pedestal. It isn't very constructive, though.