Well, the founder of Christianity didn't disown the God-sanctioned/God-committed mass killings and ethnic cleansings of the First Testament. In addition, the Catholic Church built a solid theological work on the notion of "just war". A religion is largely a matter of interpretation. What matters is not so much the original material as what people make of it.

Well, the Catholic Church for centuries was a serious part of European political machinery and our politics weren't always peaceful.

One could argue that nowadays some religions play similar role, btw.

I think a large part of the issue is that the Church's original pacifism is not a viable strategy for a state religion. Pacifism worked for Gandi, but against Visigoths or Mongols? Not a chance. So the Church had to shift doctrines (again showing that you can find what you're looking for in the Scriptures if you look hard enough) to "win the race", so to say.

> the Catholic Church for centuries was a serious part of European political machinery and our politics weren't always peaceful.

In many places it still is. As is the Orthodox church.