A Bitcoin node simply doesn't consider BSV blocks to be valid, they break Bitcoin's rules, that's what makes them hard-forks and is not related to this discussi

A Bitcoin node simply doesn't consider BSV blocks to be valid, they break Bitcoin's rules, that's what makes them hard-forks and is not related to this discussion. When there are multiple competing valid chains, with PoW the main chain is whichever one has the largest amount of work done. Eventually everyone converges to the same chain automatically. With PoS, how do you objectively chose between two competing chains?