There might be good reasons to oppose particular hate crime legislation, but the argument that such legislation, at least as it has been drafted so far, constitutes "thought crime" is not one of them. The argument is as fatuous as it gets. Here's how it has been used in my experience: "To find that something is a hate crime requires us to delve into the perpetrator's mental state; therefore, it criminalizes the mental state and is an Orwellian thought crime."
Most crimes require delving into the perpetrator's mental state. For example, intent is an indispensable element of many crimes. If I kill you without intending to, it could just be an accident, for which I may not be criminally culpable, but if I meant to kill you and especially if I had malice aforethought I am a murderer. Does that mean murder is a thought crime?
As far as I know, no hate crime legislation promulgated to date makes hating a crime. It's only a crime if you do violence to someone on the basis of that hate. Hate all you want, haters! Hate openly so we'll all know to shun you. Just don't act on your hate violently.