Your point about recidivism (if you want to call it that) isn't a bad one, will. I'd buy that, but to me that speaks more to the failure of our justice system to address the causes of crime and rehabilitating criminals than it does to the need to have specifically designated hate crimes. And/or the problem that we have with letting violent criminals walk to make room for people who were hanging on to too much weed on their way to a party.
As to your point, manic, we have laws in place which specifically protect children, women, the elderly and the disabled because of the perception that they need more protection because they cannot protect themselves. With the possible exception of women (because that might step on some gender equality toes), I don't think anyone would argue much about the importance of the law in protecting those groups of people. Personally, I don't feel that race or sexual orientation or creed is in quite the same category as people who physically are less able to protect themselves from crimes, so that it is not a necessary classification.