I don’t even think I need to mention who Harry Turtledove is - I bet on liberal forums I would probably have to or they look him up. That is why I think a boycott of him by the right would be devastating to him - I bet that is most if not all of his reading audience.
It only stands to reason that Turtledove would be a liberal. They all live to rewrite history.
People like the one you mentioned are almost always paid "internet consultants" from some Soros/DNC founded "advocacy" group. They get paid not only by the post but also by the response. Remember each time you reply to one of them, THEY get paid and all you get is aggravation.
When I first got on twitter years ago Harry was one of the first people I followed. I asked him a few times why he was alienating loyal readers like me with his hyper-partisan political tweets. He never responded and I unfollowed and haven’t bought one of his books since. To be honest his last few years of books have been crappy anyway. I end of the Civil War series was just WWII with the names changed. My guess is he gave a grad student a few notes and she wrote it for him.
Sorry, never heard of him.