I've never boycotted an entire network because of their shows, but I've definitely made the decision to stop consuming a show if it's homophobic, sexist, racist, transphobic, or perpetuates a number of other problematic attitudes (and then I usually make note of the writer/producer and avoid other work by them). I've found that most networks don't have ONLY good shows or ONLY bad shows. Take MTV for example - I think most of the shows on it are complete junk, but Teen Wolf is actually an extremely well-done show. But that's because of its creator/writer, Jeff Davis, and the cast and crew.