Yeah, I suppose we like to think that someone we admire shares our values. People like Beck are invested with a certain "image" that sometimes it's difficult for them to shake off. The whole "slacker" thing of the beginnings, for example, was put on him by perceptions.
I'm a big fan of The Stone Roses - as I said before elsewhere - and their fans can be really strong-minded in their views of the band. To many they have an almost prophetic status. When in 2012 they played a secret corporal gig sponsored by Adidas and later played in Dubai, some took it really really badly, saw it as a total sell-out, despite the fact that Ian Brown, the lead singer, has been a testimonial for Adidas for years, a brand that many fans buy too. I think a lot of the disappointment came more from the image the fans had built of their idols, rather than a u-turn on personal convictions on the band's part.
I'm sure that Beck's affiliation with Scientology has not gone down well with some fans, as it may go against the image of him they had created.
As for little things we put upon him: I thought he's a vegetarian (which has no basis whatsoever, I don't even know why I would think that! I'm not a vegetarian, so it's not as if it would "please me" if he were), he doesn't smoke (never saw him with a cigarette), he doesn't do drugs (I might have taken that view because of his affiliation with Scientology as I understand they're very anti-drugs), he drinks in moderation if at all. None of these assumptions may be true!