Shia - Sunni issue.

[Anomalocaris]

These assholes kill people who don't believe their religion because unbelievers are "infidels". They also kill EACH OTHER because of slight differences of opinion.

This only illustrates why Islam is a pox on humanity and the world would be better off without it. Even if Islam took over the world, everyone would end up dead because they'd just start killing each other.

Christian very likely killed many more of each other because of slight differences of opinion.

I think Islam is disadvantaged in comparison with christianity because christianity has put on sheep's clothing and therefore Islam now seems alien and conflicts more glaringly with our more superficial cultural sensibilities. But I think Christianity is at its heart more adaptable, more unscrupulous, and more focused on flanking attacks upon the fruits of enlightenment, and is therefore a more dangerous threat to progress and enlightenment than more brutal, more ugly, but less cunning and effective Islam.