Wendy Kaminer had a great piece in the October 26th Wall Street Journal. In "The Return of the Though Police" she characterizes hate crimes as punishment of the thought or ideas that accompany a criminals commission of an act. That is, a "hate crime" is nothing more than a package of a crime and the thought that goes along with it. As such, it is a false concept, and leads to the politicization of crime.
Still, distinguishing hateful bias crimes from other hateful acts of violence punishes ideas and expression, no matter how scrupulously the legislation is crafted. When someone convicted of assaulting one woman is subject to an enhanced prison sentence or a more vigorous prosecution because his assault was motivated by a hateful belief in the inherent inferiority of all women, then he is being punished for his thoughts as well as his conduct.