Frustrated, I could understand, but incensed is just a small step below rage. IMO Everyone is entitled to their opinion/viewpoint no matter how abhorrent anyone else may find it. I never let it affect me unless it's someone whose opinion I value or they are in a position to form public policy.
Everyone is entitled to their opinion. Nobody will disagree with you on that. That entitlement to one's own opinion is why people give opinions on other people's opinions.
I'm not exactly sure why that point gets brought out of the barn so often... Actually, I do know why, but whatever.

Regardless, people's opinions are... typically how they vote on policy. So I see no harm in challenging people's views.