My biggest question when it comes to PoS security.

Please educate me.

So with PoW every additional block makes all previous blocks more secure because changing any past block invalidates all work done in the following blocks.

Does PoS have this same property? If so how? If not aren't the PoS skeptics at least partially right, PoS isn't as secure as PoW? I mean even if this is the case it doesn't necessarily mean that PoS isn't secure enough, but it would be interesting to know.

Thanks again!