Well I agree that as a concept that foreign terrorism is an act of war.. But what of domestic terrorism? What of OKC or the Unabomber? Also, it _is_ a crime under federal law.
Whether we treat an act of terrorism as a crime or an act of war is the same as asking whether we put the perp on trial or shoot him in the head (or ship him off to gitmo). That there is a federal law against terrorism, though, shows that the government is (in some cases) prepared to treat terrorism as a crime and not an act of war. Or at least, a crime first, and an act of war second.
It is horrible that someone should want to assault someone because of their race or sexual orientation... but I do not think that makes it worse than, say, someone who assaults a child because they are a vile pervert. Look to the crime, not the motivation. Or leave it to the judge and jury who know the facts of the case to decide, not to some knee-jerk hate crime law.