Free speech is not a crime, and condemning the government of Israel is no more anti-Semitic than condemning the government of Great Britain is anglophobia. The first amendment isn't a grant of privilege, it is the recognition of preexisting inherent human rights not based on geographic or political whims.
Sadly, that is an understanding of things that is seriously lacking these days.
Too many on the "left" and "right" start their arguments with something like, "It's my right as an American..." and completely lose the plot from the get-go. Governments don't grant rights. They either respect or (more often) trample rights inherent in individuals, including free speech and voluntary association.
I really have nothing to add to that...