Defend someone for exercising their rights despite facing criticism and threats. Explain why they should not feel obliged to support people who criticize them because of their political beliefs.
He needs to ignore those idiots.  He did nothing wrong, except exercise his rights.
He does need to understand that those criticizing and making threats are those on the LEFT, the DEMOCRATS that many of his people vote for.
Maybe, he will consider why he is told he must support them, when they are so ignorant of reality..