Short version It's hard-wired to followers of Abraham-based religions (ie. Christianity, Judaism, Islam) but Islam is the villain because they aren't white
Long version Christians been doing this throughout the history, old habit dies hard. Christians been wandering around, put the sword to people throat (later on, guns, cannons & a piece of paper) & force them to convert for almost 2000 years now, what can you expect from these warlike people? The Catholics got the divine comedy that stated all non Christians will go to hell. But whatever, the Muslims also said the same thing but as said, you think they're the bad guy because they aren't white so I say racism also play some roles. Also, keep in mind Christianity once used as a mean to conquer Europe during the dark age, back then Christians are terrible terrible people who love to bash other religions & spark riots to burn down cities & slaughter non Christians.
It also has to do on the teachings telling you to beg & rely yourself to this man who died on the cross because that person "died for our sins" because that person is god & god love us so much to send a fraction of the deity to die here just to revive again in 3 days because the deity loves all of us & this death is to die for our sins. Because that this deity "died" it cleanses us somehow & we have to be grateful & rely ourselves with the deity in order to get to heaven.
That doesn't make any sense at all!!!
It also has to do with the fact Christians love to brainwash their children with stuff from the religion to the point all they can ever think about the world will be based on the book. That makes their children ignorant, arrogant & close minded. When these children grew up, the cycle continues & this is the product. Nut Islam also do this, but you think they're the villain because they aren't white
My country achieved religious peace even before Columbus discovered America, but the main reason is because the dominant religion isn't Christianity, go figure!
I don't feel that that is so much a matter of religion as it is of ego. In these matters, it is expressed through a religious context. What I mean is that people are so determined that they are absolutely correct in some thing or idea that the thought that some other alternative could possibly be true is alien to them. You can see this just as well if you ever take up a political discussion.
Also, to answer your question, my personal opinion is that there is no point whatever in disrespecting another person's beliefs. The fact of the matter is that no matter how fervently you may disagree with another person's spiritual beliefs, they will never have a direct effect on you one way or the other. If they choose to believe something that you don't, and it turns out they were wrong, well, they were wrong. Doesn't effect you. If it turns out they were right and you were wrong, well, you were wrong, and that is your own fault and not thiers. It's a wash.
I used to ask myself that a lot too, but I think I'm starting to understand it now. In some religions it's required to not get along with everyone, even if there's a rule somewhere stating that people have to get along anyway. Take Christianity for example. Yes, it's true, as a Christian you're supposed to love everyone, no matter what, in as divine a way as you possibly can. However, you can't just NOT tell someone they're not going to hell because according to you, that would be a lie. In some cases, but not all, it's not that Christians hate or intolerant of other people, cultures, and faiths, it's just that their faith insists on being true and as a result: they can't accept other religions as true ones.
While it sounds like Christians are breaking their own rules and judging people, condemning them to hell for whatever reason, in some instances it's not. They're just stating what they believe to be true, because it's very hard to put it any other way. The more nicer you try to make it, the more false it becomes. You can't just go, "Oh, whatever floats your boat, it's your religion," because in your faith there is no other religion.
Not telling someone when something is up is like lying too, even in non-religious cases. Say you're gay and you're afraid to come out to your parents about it. If you ended up not doing so, provided you were aware of your own sexuality, it would be lying. Because as far as they know, you're straight. Even though you're not. So if a Christian finds their self in a situation where they have to be upfront like that, they will. Compared to the situation of you being 'in the closet', however, telling someone they're going to hell is a lot easier because it doesn't have very much affect on you personally. Especially if you're telling a total stranger. It's so much easier to tell a person they're going to hell and feel better about it than it is to tell your own parents that you're gay, because there are severe consequences (in most cases) for being gay than there are for telling someone they're going to go to hell. It's not that you're being mean on purpose. You're just telling it like it is. The 'truth', which in this case, wouldn't hurt you because you're not the one...going to hell, as it were.
And that's just the nicer Christians.
The meaner ones go around looking for things to put down and hurt because they feel it's their right to do so (even though it's not, according to their own law). The meaner ones, in other words, use the Bible as an excuse to bring others down. Sometimes it looks like they actually enjoy it. They're the bullies of the adult world. They may see non-Christian people or sinners as the 'weaker' being, and therefore seek to make themselves feel better by bringing said non-Christian or sinner down. They don't care if what they're doing is wrong or not or true or not. They just want to see someone else get hurt.
I gues if they are telling the truth and meaning no harm then it would be okay, but what you said in the last paragraph is not okay for people to do (which I do believe you'd agree with me on that considering you called them bullies and whatnot).
Yeah, it sucks that it happens, but it does. It might be in-humanistic of me to say it, but people really are selfish like that. It's human nature. A defense mechanism, I think. We're social creatures, but when we feel threatened or weak ourselves, we have to attack other members of our own species (and some times of other species) to pick ourselves back up again.
In some people's religion you are told you have to go out and spread the word of God and point out their Gods are obviously fake and faulty. So for some people it's a religious requirement to not get along.