No in several ways. 1: The definition of an acceptable transaction is a part of the protocol. Being a block validator or attestor doesn't let an entity change

No in several ways. 1: The definition of an acceptable transaction is a part of the protocol. Being a block validator or attestor doesn't let an entity change the rules of the protocol. 2: intentionally excluding transactions from the Blockchain (essentially censorship) causes economic harm to the PoS censors and is ultimately futile. The fine article discusses both these points in more depth (mostly in the misconception section). Essentially stake in a proof of stake system is used to punish selfish/destructive behaviours and reward honest cooperation. Participating in that system does not create a 2 tiered system of participants where one tier has powers the other doesn't not. Nonstakers simply do not aid in the production of blocks and therefore the incentive mechanisms of block production do not have any impact on them.