Once it had been explained to me, I found it pretty simple.
When you single out a group of people as a target for hatred and violence, you assault a whole community (where "assault", legally speaking, includes "threatening"). So we made a law to make it clear that inciting hatred against a visible group of people is a crime.
So if you beat up a black guy or a brown guy or a gay guy, you're only guilty of "aggravated assault". That means, basically, "causing bodily harm".
But if you repeatedly assault members of the same group over and over again in a way that intimidates others of that group, well, you're not just guilty of aggravated assault in each case, but of "assault" against the whole community. Y'know, seeing as they all have to worry about crazy ass bigots beating them up.
Unless of course, you've got your blinders full on like these guys over at Christian Governance.
Then it's all about how those pansy-ass liberals are bent on keeping the poor, beleagured white male down. Oh, poor white males! How ever will they cope?!