How does blockchain solve the Byzantine General's problem without relying on a (corrupt) central authority? Math or not, police & courts overrule them. Actual

How does blockchain solve the Byzantine General's problem without relying on a (corrupt) central authority? Math or not, police & courts overrule them. Actually, blockchain isn't even mathematically a solution to BGP, is it? You need to define your actors better, here. A 51% attack means communication can be denied. And there's still the question of how does A know that B has seen that A has seen, that B has seen… Am I missing something? The fact that communication happens on the blockchain doesn't mean it's not communication. I just read a couple of articles about blockchain and BGP, and I think they all misunderstood what BGP is. I'm A, and see that B is "committed on the blockchain to attack, assuming A is too". I can then add my block that says "I see B commits to attack. I agree let's both do this. I'll attack if you attack". Ok. So now B sees that. Do they attack? If you think the answer here is clear, then you've misunderstood BGP.