This is a bad take and won't convince anyone who understands it, even though it has a grain of truth.

The reason bitcoin required proof of work is not a vulnerability of proof of stake (although I agree it's less secure), but because the stake would have no value. PoS needs something scarce and valuable. Bitcoin was scarce at the beginning, but it did not have much of a value.

Increasing money supply - nope, stakers cannot increase money supply, pos/pow is consensus on the history, not the rules of the system. The mechanism that would lead to increased the money supply would be exactly the same in both pow (like bitcoin) and pos - change of culture, or social consensus (as opposed to automatic bft consensus).

So no, don't talk to PoS people like this, it just shows you don't understand the mechanics of consensus and it will certainly not make them change their minds.

The good part is that the stake which is internal is a chicken and egg problem - using something that you are trying to secure (from the past) to secure the future creates long range attacks. PoS chains would just fall back to social consensus in this case, but it still sucks.