But in the real world, the Ukraine was refused entry into NATO before the war, exactly to avoid pissing off Russia.

Here's your argument, as it really goes:

"My neighbor has guns. I have a lot more guns, but I decide I am threatened by my neighbor, so before he ever does everything, I break into his house, kill his kid and rape his wife, just in case."

Your argument is paranoid. Your argument is evil. Your argument is irrational. Your argument is disgusting. It shows you are a morally empty person. It shows you are an unthinking brute.

Preemptively attacking a person or a country who has never offered you any harm is wrong.