These people are multi-millionaires who are living a life 99.9% of other Americans can only dream of.
Everything is at their beck and call. The finest food, private planes to exotic locations, the hottest women and nightclubs.
Why the Hell would they want to concern themselves about politics or who is in the WH? How exactly is Trump hurting their bottom line?
Two reasons:
1. They think that most of their fan-base is in agreement with them, so they think that they are doing themselves (their careers) a big favor by issuing such public statements. - A corollary: They wouldn't get as much coverage ("good publicity!") if they made pro-Conservative statements (the journalists would ignore them).
2. Deep down inside, they realize just how inconsequential they are, and believe that they can counteract that by making "virtuous" public statements.
Then again, they might only be "mouthing off" without thinking of the consequences.
Regards,