I think that may be overgeneralizing a bit. I don't think religions necessarily hate each other, although some do. Christians and Jews get along just fine. Hindus and Muslims have no love for each other but Jews and Christians have no issue with Hindu. Christianity and Judaism have no issue with Buddhism and in fact one can use Taoism as a way to go about life while practicing Christianity.
Frankly, the only conflict I see is with Islam who pretty much everyone hates, but primarily because Islamic extremism hates pretty much everyone else. Certain religions may disagree, but that doesn't necessarily make them mortal enemies.
As far as Christians taking the US by force...that's not a Christian thing. Atheists took Russia by force, they took China by force, Cambodia, North Korea, the list goes on. Any time land gets conquered it is "
taken by force" no matter who is doing the conquering.

It has nothing to do with religious identity and everything to do with the nature of conquest.