You are still free to protest. There is a difference between protesting government policies and organizing boycotts of the country. Feel free to protest by publishing letters stating your opinion, carrying signs in streets, etc. If you want to boycott products on an individual level, do so. Just don't go around calling on people to boycotting the country. That's illegal, as it should be.
U.S. Democratic Sen. Bill Nelson announces support for Iran nuclear deal (Haaretz)