Public figures have a right to sue under certain conditions. Just ask some of the tabloids. I have litigated and lost NY Times vs. Sullivan issues and lost. Foreigners have rights to sue in this country. An Asian airline has recently sued a US TV station for comments perceived as racsist. Do I think anyone will get anywhere with the suit? No.
Continue to lead with your chin if you believe to the contrary.
The expense of a lawsuit is more than damages. Try paying for defense without insurance.

I'm not encouraging people to sue anyone. I'm just hoping that a little more civility and gentlemanly manners can replace some of the vitriolic, personal attacks.