Last I checked Nazis were not a protected class in any state.
No, but if they were as homosexual marriage is then the argument holds. If it was against the law to discriminate against Nazis, and the right to use the swastika was treated as sacrosanct, then a baker or a sign maker who refused to use his talent to create a work using it would be considered guilty of discrimination, if the gov. was consistent with its punishment of Phillips.