I don't think most people have even the time to play on all platforms. It's really tricky if you have a full-time job, let alone children. At least for me, one console is more than enough. Of course that doesn't mean you need to become a fanboy. But it's just human that you start to like things you spend a lot of time with. Me personally, I try not to disrespect other consoles, but I like some good fun every now and then. It's just sad that so many people switch to RAGE mode just because of a little joke. Like "I can't wait to play Halo 1 on my Xbox 1 this fall!". I mean, come on, even Xbox Fanboys must admit that's kinda funny. Stop being so defensive!
Anyway, it's not too bad overall. When it comes to smartphones it's much worse, because that's where the masses are. I just bought an iPhone some weeks ago and oh my god, my friends almost killed me. There were the android guys who said that the phone sucks so much, yaddayaddayaddda. Then there were some apple guys who said I'm stupid for not waiting for the iPhone 6 (like I would care, I needed a new phone NAO, because my old one broke). And then there was this single windows phone guy who almost begged me for buying some Nokia phone.
There are fanboys everywhere, it's not just gaming. Fast food, music, movies, even clothing. Like I said, it's kind of a human thing. And I believe everyone who says that he isn't a fanboy in the slightest way is kinda lying to himself. It's like those people who say they aren't influenced by advertising. You may not notice, but that doesn't mean it's not happening.