I've participated in many communities where this sort of tribal behavior is present.
PS3 vs XBOX 360 was a fun one. I don't own a gaming system anymore, but I did catch wind of the release of the next generation of consoles, the PS4 and the Xbox One. I've already caught glimpses of trash talk between the loyalists from the two camps on my Facebook feed, and neither system has even been released yet.
Apple vs Android as another one, and it's one that I was more heavily involved in. I hate Apple products, so I was always recommending Android alternatives to people. This of course meant that I had to defend myself from the Apple drones who were quick to try and shoot me down.
I am a Vancouver Canucks fan, and if you follow NHL hockey, you know that my team has a bad rep. The trash talking on sports forums is the worst because the average sports fan is . . . well let's just say that they're more brawn than brain. When we lost the Stanley Cup Finals in 2011 I could not read anything on the internet about the loss for months because of all the haters that took the opportunity to dogpile onto the Canucks.
Now I'm into cameras, and it's no different. Canon and Nikon are like the Illuminati and Templars, centuries old foes that will fight each other until the end of time. Pentaxians are generally well behaved, but they do
get defensive once in a while. (Also see the PZone review of the DA 18--135 WR).
But the writer of the NYT article linked in the first post on this thread hit the nail on the head when talking about Leica. I can't remember why, but a while back I found myself browsing the L forums. It's another level of fanboyism.
I've heard/read that the audiophile community is the most vicious tribal subculture of all.