I'm gonna go ahead and throw it out there... if you belong to Interference, you like them for their music and not just to drool over the band members, chances are you're a 'true' U2 fan.
In short, no, you don't have to like Pop and Zooropa and Passengers and be 'different'. You can love all of Bomb, Boots, Crazy, Elevation, blah blah blah, and be a true U2 fan. Gimme a break. It's all opinion based. The only difference between a true U2 fan and an average fan is the ability and knowledge of all of their material. I still know every Pop song, I just don't like most of it. I still know every Zooropa song, I just don't like most of it. Yeah, and the majority of the people are indifferent about October. I also love that album. Everyone has their own taste, and it doesn't make you less of a fan.
I'm still a diehard U2 fan, and they're my favorite band. So I love I'll Go Crazy if I Don't Go Crazy Tonight. Sue me.