If I kill someone in self defense I didn't harm him by mistake. Sometimes you even have to kill people even if they don't pose an immediate threat to you.

Well now you're moving the direction to a different topic, but yes, that's already covered. Intent changes the punishment -- no different than any judicial system.

Doesn't mean someone may not attempt to become a blood avenger, but God is judging someone based on their heart; man will give you a trial based on circumstantial evidence.

What is true Christianity or who is a true Christian has no clear definition.

It literally does, in the Bible. In no uncertain terms, in no interpretative confusion, it literally states in John 15:10...

"If you keep My commandments, you will abide in My love, just as I have kept My Father's commandments and abide in His love."

That's it.

Catholics think you aren't a true Christian. What about Greek Orthodox? Russian Orthodox? Mormons? Jehovas Witnesses?

It literally does not matter. This ties into your angst against organised religion. If all these other religions are professing martinet style rules over salvation, they've already stepped away from the simple teachings in the Bible.

Are you following Jesus' rules as dictated by the Old Law? Yes? You're good. That's it. Anything else is confetti and noise.

The Church (who claim to represent God on Earth) only cared for itself.

Yes, just like corporations who get greedy abuse the laws to create crypto-capitalist corpo-states that operate more like oligarchical socialist hierarchies. Does that mean capitalism is bad because corporations claim to be capitalist while fixing the institutions so we no longer have proper free market reign?

What caused it was Christian compassion for thy enemy. Jews are supposedly the arch enemy of Christianity. The synagogue of Satan. And yet Christianity never once tried to actually end their enemy. Christians have always been the most steadfast supporters of Judaism. They emancipated them again and again and again.

I don't disagree, and, in fact, this coincides with my point: they abandoned the tenets of the First Principles.

God always forewarned NOT to adopt, abide by, nor enable religious practices that take you away from Him. Enabling heathen practices is how so many of God's chosen fell before, in fact, first and second Kings literally details how this happened over, and over, and over again because the kings literally did exactly what you said, and only less than a handful of the rulers actually maintained the original Commandments.

The only people who truly tried to solve this problem were pagans. And they were fanatically attacked by the Christian world.

And now that the pagans rule, we have millions of White babies being aborted, White persecution, promiscuity, the dissolution of the family unit, and 40 years until complete civilisational collapse of developed nations. How do you reckon that this paganistic secularist solipsism is better for you, when you've just spent the last couple of days complaining about the outcomes of that secularist society causing great distress?

As long as we aren't able to prove or disprove Gods existence we'll have to agree to disagree.

Actually, God's existence is proven through quantum uniformity.