but we can absolutely stop wars and opression, violence and hatred.
Yeah, but not really.
We can stop wars. But there are multiple ways to do so. And since there are multiple ways to do so, we would all have to agree on which way we want to stop wars.
Do you stop wars by becoming a superpowerful nation and destroying all oposition until nobody can rise against you anymore?
Or do you stop wars by getting the leaders of every country together and agreeing not to produce weapons or fight anymore? Well if you do than and just one of those countries decide to build a secret military, then they would have a GIGANTIC advantage and take the world by storm as everyone else has no military.
We can stop individual cases of violence, but how do you stop ALL violence?
By operating a maximum survielance police-state where every individuals moves are carefully monitored, and any hint of deviation is rooted out?
Or do you stop violence on a social level by just encouraging people to be polite and kind to each other? Well the problem there is, it doesn't work. Sociopaths do exist and they don't care about your ethics.
Surrounded by people who only do good, the evil person will thrive.