I consider that speech, while being rephrehensible, to be protected. It is an act of peaceful protest. He has the right to state his opinion on current events, no matter how vile.
Yes, I believe that sort of thing should be protected.

I think the "women belong in the kitchen" should also be protected, but it's not - it would be considered "sexual harassment" even though men and women are supposedly equal(if a woman said something similarly derogatory about a man, nothing would happen). Those kinds of things are, I consider, political opinions.
However, you also have to look into the intent. If the "women belong in the kitchen" banner was waved outside of a women's organizational meeting or something, it could be considered a public disturbance - and that should not be protected. However, everybody has a right to have and to state their own opinions in a peaceful manner, which should always be protected.