If you are genuinely entitled, you are probably entitled by law, by convention, by the terms of some contract. There's some framework, and some reason within it, that you are owed the thing.

We also seem to use "entitled" to mean that someone thinks they are owed things when they aren't - you often find this in rants about individual jerks or millennials in general. There's no subject to be had in that use because the entire point is that it is not legitimate.

I think the latter sense is always an adjective. The former sense clearly can be a transitive verb, and I have not found a seemingly grammatical utterance that can't be described that way (I think - IANALinguist). The fact that the subject can be left unspecified is a feature of the passive construction in general, and an often-stated motivation for some of the criticism it receives.