I don't think he would use the term "anti-American" in describing himself (or anyone else):
http://www.chomsky.info/interviews/20021209.htm
The concept "anti-American" is an interesting one. The counterpart is used only in totalitarian states or military dictatorships, something I wrote about many years ago (see my book Letters from Lexington). Thus, in the old Soviet Union, dissidents were condemned as "anti-Soviet." That's a natural usage among people with deeply rooted totalitarian instincts, which identify state policy with the society, the people, the culture. In contrast, people with even the slightest concept of democracy treat such notions with ridicule and contempt. Suppose someone in Italy who criticizes Italian state policy were condemned as "anti-Italian." It would be regarded as too ridiculous even to merit laughter. Maybe under Mussolini, but surely not otherwise.
Actually the concept has earlier origins. It was used in the Bible by King Ahab, the epitome of evil, to condemn those who sought justice as "anti-Israel" ("ocher Yisrael," in the original Hebrew, roughly "hater of Israel," or "disturber of Israel"). His specific target was Elijah.
It's interesting to see the tradition in which the people you refer to choose to place themselves. The idea of leaving America because one opposes state policy is another reflection of deep totalitarian commitments. Solzhenitsyn, for example, was forced to leave Russia, against his will, by people with beliefs very much like those you are quoting.