This is a standard argument against hate crimes. And I think there's some merit into it, but it's ultimately incomplete and really leaves the case for hate crime legislation hanging.
I think he's blurring a few issues here. Hate crimes legislation doesn't intend to perfect human nature, it seeks to distinguish crimes that are, in my opinion, meaningfully different. I think the term "hate crimes" seems to focus too much on the emotion and belief of the perpatrator; the real focus should be on the intended effects of the crime, and therefore, I'd just call almost all hate crimes "terrorism."
First, Hate Crimes law has never been about regulating speech or belief. Neither is constitutionally permissible or and the latter isn't possible anyway. You're free to go to Klan rallies or Pentecostal churches or neo-Nazi meetings and say whatever you want. Keller says that "the government is authorized to punish you for thinking those vile things, if you think them in the course of committing a crime," but that's not exactly true. The government is authorize to punish you not for thinking those vile things but for committing an act motivated by those vile things. Similarly, you can be punished differently for a murder intended to eliminate a witness, and we're not surprised that your thoughts, intents, and motivation affect your sentence. If your motivation is independent, you're off the hook, at least on that wing.
He also spends too little time on the point that hate crimes are different because they terrorize an entire community, saying that any crime will instill fear in neighbors. True, all crimes do that, but all crimes are not intended to do that, and I think that's a very important difference. If you break every window of every synogogue in a five mile radius, your act has a fundamentally different effect than if you're just causing random mayhem. You are aiming your gun at people not present, and illegally coercing them. You create a very real and immediate threat of violence to those who aren't your victim, and it's not a side effect but your intended act. That's a real problem, and not one that's captured if we treat all acts of vandalism equally without noting these community effects. Furthermore, you're either tacitly or explicitly recruiting by acting this way. Perpatrators of hate crimes don't see themselves as criminals, like a mugger does, but as heroes. When uncaught, they seek to define their acts as those of the community, and when captured, they hope to be a martyr to the cause and inspire others to match them. Again, these aren't true of ordinary crimes.
He then skips past arguments that we must protect the vulnerable by pointing out others are vulnerable, too, and we don't protect them. But we do! And I'd happily argue that we should expand those protections. And we never have hesitated to punish pedophiles differently and worse than other sex criminals. We're happy to pick out these motivations and bring down more justice.
This is another red herring: "The distinction Hurd makes — convincingly, I think — is that when you penalize intent you are punishing matters of choice. One can choose not to pull the trigger, not to throw the rock, not to steal the purse. 'You can’t choose not to be prejudiced or biased — at least not willy-nilly, on the spot.'" No, you can't choose not to be bigoted. Not really. But we're not really asking citizens to forbear their bigotry. We're asking them not to commit crimes motivated by bigotry, to keep their bigotry nonviolent. And that's far from an impossible task.There are patterns of violence which you can't participate in and pretend they're outside the pattern. They're manifestly different crimes. And sure, we can't execute people twice, so to some extent, hate-crime-murders aren't really important, it's all the other crimes where there's a scale to be made. But this isn't about trying to convert the hateful. It's about restraining behaviors to remove specific threats to the peace which differ from their underlying crimes.