Where I grew up, there was one black student, one Indian student, one Native American student, and one Japanese student + three foreign exchange students.
Indeed, one of those foreign exchange students was from Finland and lived with my family and the one class we had together was taught by the teacher who called by nephew a racial epithet. He also told Petri that he was a Communist. And when Petri said Finland wasn't a Communist nation, the teacher said, "well, you don't understand the facts of your own nation."
Of course, this could turn into how bad public education is (and my school was rated one of the finest in the state of Indiana at the time) and I'm not wanting to turn it into that; but history should be taught from all perspectives - not just the White American perspective.
The teaching of ethnic studies courses is a response to traditional academia telling everything from a single perspective.
Until THAT is changed, I see no problem with ethnic studies courses. I, myself, minored in African-American studies and loved every minute of it and learned a lot that I didn't learn from more mainstream courses. It didn't develop a "separatist" perspective at all. It developed understanding between people.
Unless the law address the way history is taught in general, to ban ethnic studies courses is nothing but yet another political ploy by a bunch of politicians who are worried about a bunch of pissed off white folks who are really (and legitimately) angry and don't know what to do with their anger.