Well, the reality is that while it seems glamorous and magical to us, people who work in Hollywood tend to have an "another day at the office" mentality. They're working in the sausage factory, as it were, and the "hopeful humanistic messaging" is just the stuff they're being paid to pack into the "product". You know, think Galaxy Quest.
I'm not saying nobody in Hollywood drinks their own kool-aid, but there's a reason why Shatner agreed to do the Get a Life skit or why Nimoy wrote I am Not Spock.
The difference is that in the old days it was expected that if you do interviews you maintain your serious front, talk about how what you're doing is going to lead to world peace. But we're in an era where politeness and decorum are an endangered species (witness our President, for instance) so that's why, more and more, people in Hollywood just act like everyone else as far as being some combination of rude, self-absorbed, crude, and confrontational. You know, somewhere on the Kevin Smith spectrum.
I do miss the old days when celebrities sort of followed an unwritten rule to act sort of like royalty, never saying anything that you wouldn't want to be said around the family dinner-table, but those days are over.