Interesting post and I'm sure that is true in many circumstances. One would think though, that the likes of Julia Roberts and Whoopi Goldberg would be big enough stars that they could at least refrain from outlandish remarks.
Some big actors seem to have be able to circumvent the unions. Thinking Tom Hanks for example, I don't recall him ever publically swinging right or left. His wife may play surrogate in his case though.
Prairie
Left, sadly.