Hollywood is also an echo chamber, everyone in Hollywood that is not extreme-left gets rejected and blacklisted which results in more alphabetsoups being part of the group as you have to be pretty darn left to reject biological realities.
This is the same as saying that there are no alphabetsoup JW's and all JWs normalize child sex offenders - which is true, leftists in general would not be attracted to the message and anyone that does engage in practices or points out the sex offender problem gets promptly kicked out of the group.
There are conservative filmmakers, quite a bit of the best films in the 70s and 80s came from right-wing figures. Some of the best actors around both established and up-and-coming are conservative. You don't hear from them because they have an uphill battle getting recognized. But Jerry Bruckheimer, Matthew McConaughey, Adam Sandler, Vince Vaughn, Joe Pesci, Scott Baio, Jon Voight, John Wayne, Clint Eastwood, Charlton Heston, Keanu Reeves are or were some of the best actors and directors in history, and you haven't seen a good movie since Hollywood started actively blackballing some of these actors - literally look at the top rated movies (by viewers) of all time, the last one was The Dark Knight (2008) which was more than 10 years ago now.