If you introduce concepts which favors those that has the most resources (having more coins, more ASICs), then you reach the same degree of centralization. That argument is valid for both. The argument for PoW and against PoS is that there is a greater opportunity costs for PoW than PoS, in the case of a rogue miner. They stand to lose both the value of their coins, the equipment, the resources spent, etc.

In the case of PoS, they can support multiple forks without losing out. The degree of fault tolerant for PoS is 1/3 of the network going rogue as compared to 1/2 for PoW.