Sure, those attacks happened on lesser-known chains like Ethereum Classic and Bitcoin Gold, but doesn’t that actually suggest PoS is more resilient in practice, even if can be argued that it’s weaker in theory?
In PoS, to extract value or compromise finality, an attacker needs to control 67% of the stake, which has never successfully happened, even on unknown tokens or forks from popular chains. That’s a pretty strong track record for security and resilience.