What is the deal with fanboys?

Why are fanboys so aggressive when it comes to speaking about what they like? I don't have a problem with fans being passionate about what they like, but the thing that I can't stand is how aggressive they get when it comes to people. For example I love Pepsi, and I think it tastes better than coke. But if I say I like Pepsi around certain people not only will they mock me for drinking it, but I have meet some people who act disgusted. I mean me I will drink both, I just like Pepsi more. Or on the internet you have entire "flame wars" about xbox vs playstation. First of all as far as a technical standpoint both have pluses, and minuses. But from a game point of view they both play 90% of the same games. Yet fanboys will constantly insult each other saying anyone who doesn't agree with them is an idiot. No matter what product there's out there there are always going to be 2 groups who support a product, and resort to childish name calling for anyone who like a competitor's product more. I have NEVER heard a fanboy present a logical argument for why iphone is better than andriod, or why Star Trek is better than Star Wars. Most of the time they simply say you're too stupid to understand it anyway, or some other blanket statement insulting the other person completely ignoring why the other person likes their product. Why can't people just respect other people's choices without making it a personal war of insults?

Breaking the Internet. I wouldn't advise you to do that, you won't get many answers here. Most of the people here are simple bored trolls, looking for attention. Only a few of us are actually real.

Pepsi (Merica')
Xbox (I own both Microsoft's Xbox One and Sony's PlayStation 4)
Star Trek (Simple because the original Star Trek had William Shatner)
Irony

Because they are insecure, and by making themselves feel "right" they feel better about themselves and superior to others who disagree.

Interestingly, the same thing happens when people argue about one belief system, or lack of belief system, over another. PS4 versus XBone and Trek versus Wars are just variations of Christianity versus atheism.

This question violates the Community Guidelines.

The reason people 'fanboy' or 'fangirl' is because they have become infatuated with the said being subject. It is like your first grade school love. She is just oh' so perfect and if anyone says anything about her you wish nothing more than just pure malice and spite toward them.

The real question is why do you feel the need to cry on a messageboard about it? Thats the real question here.

Fanboys are just that fanboys. You should expect them to be aggressive, incoherent and dead set on saying their opinion matters while yours does not. It's not like these are rational people who you can expect to have a rational conversation. You usually encounter them on YT disliking any video that expresses a differing opinion and telling people to kill themselves in the comment section.

We all have a subject we're passionate about but these people are borderline fanatics. Their console/game can't be anything less than perfect. I usually meet their hostility with my own brand of jackass-ery. I try to ignore them as much as possible and you should as well. Never try to talk to them.