I agree that attacking someone over political beliefs isn't a hate crime. Still a crime.
Has little to do with sympathy. I think Richard Spencer is primarily a useful idiot to polarize and draw racial lines over political issues that don't need them. I don't care at all about him personally. However, creating a culture where assault is justified when the political motive is favored is basically a de facto ban on freedom of speech. When the law decides to make examples of certain politically-motivated crimes but not others, it shows inequality of the law (and yes agent00f I'm aware that American justice has always been full of bias along racial, sexual, economic, etc lines). While the guy that punched Richard Spencer may get away only because he concealed his identity (happened in DC and the feds are probably going to be more strict), other states such as California and Washington have a history of turning a blind eye to ANTIFA violence, even when the perpetrator's identity is known. This is because people think "Eh, they deserved a punch to the face, whatever".
In these specific cases, neither victim was doing anything instigating at the time. The woman in the airport was sitting quietly, Spencer was apparently answering an interviewer's questions on Pepe the Frog. Perhaps motive could be argued to be different (the guy that punched Spencer could have done it impulsively for fame as well), so I won't argue each criminal should receive the exact same sentence. The criminal in this story probably deserves to be punished more severely, but not because of his choice of victim.