That's not a pretense. The word you're looking for is pretext. Rejecting the mainstream is completely a legitimate position on its own. The only way it can be a pretense is if it's done for appearance only. Well, maybe there are other ways, but that's the only one I can think of at the moment.

Maybe this is confusing because of the phrase "false pretense", which is redundant and can lead to some people thinking that there's such a thing as a pretense that isn't false-ish.