Yeah, I can see that point of view.
Your argument rests on the assumption that longer sentences reduce crime, which is like, maybe true. It could be true in the case of hate crimes.
My current impression is that polarization around the topic of “what is a hate crime” is more trouble than it’s worth, and that the harsher sentencing of hate crimes more likely to come down on more vulnerable groups (note, in my post, the 4 black kids were charged with a hate crime, but the 3 white kids who sexually assaulted a black teenager were not.) But, I might be wrong on those assumptions in the general case.