Twenty years ago I was part of a folk music duo. We were banned from a coffeehouse gig, where we had previously been a favorite act, because we praised President Reagan from the stage. We honestly had no idea that we were being controversial. We were very politically naive at that time. We didn't know the difference between a liberal and a conservative, we only knew that Reagan was a great president. We had no idea that coffeehouse audiences were liberal, and that liberals hated Reagan AND those who loved him. Anyhow, we soon learned to read our audiences and figure out what we could and could not say at different venues. VFWs were great - we could praise Reagan all day long there.
The blacklist against conservative entertainers has done a lot to silence conservatives in that industry. I don't just mean from the stage, I mean that they won't open their mouths about their politics in interviews or campaign appearances because it could mean being out of work.
There are conservatives who are so well respected and big enough box office that they still get work but there is a blacklist.