I'm definitely a Star Trek fan!
Me too! I didn't watch all of Voyager originally, but eventually I worked my way through it. I'm working on Season Four of Enterprise now, finally. It's not great, but it's watchable. I've seen all the movies. I've watched Next Gen and DS9 multiple times. I own them on DVD. I used to watch TOS as a kid in syndication.
But I've never been to a Star Trek Convention. I don't own any merch (I don't care about merchandising for anything at all, and I'm a comic-book guy, so I admit that I'm unusual that way - it's just all unnecessary junk to me. I absolutely make no judgement against people who like it. Heck, I sell the stuff at work.)
So I suppose some people would consider me not a "true fan", but whatever. Gatekeeping is silly.