[jriddycuz]

I think the meaning becomes clear because this sense of the word is almost always used as an attributive modifier of a pejorative term: e.g., "entitled pricks", "entitled, combative princess." I agree with you that it has a much more specific meaning as a predicate compliment: "I'm entitled to my own opinion."

Language changes. People sometimes still complain about "hopefully" being used as a sentence modifier, as in, "Hopefully language mavens will see their role in speech communities as custodians and curators of beneficial older conventions, rather than as guardians and protectors of acrolectic law." However, the etymologically literal sense of this word ("in a manner full of hope") has so little use that the non-standard meaning predominates.