Banning “hate speech” without restricting political speech is prohibitively difficult because of the target’s inherent subjectivity.
That's the crux right. As soon as you decide that a certain kind of speech is "illegal", the goalposts shift to convincing others that speech you don't agree with falls in the illegal category. Even what seem like sensible categories like inciting to violence immediately get spun around and we get all sorts of things being called violence in order to try and suit political aims.Like most rights, free speech isn't perfect, it's just the least bad alternative.