Earlier quoted context omitted.
Non-infectious ignorance can be left alone. A state senator with a PR platform, using it to spread ignorance of a sort that ruins millions of lives, cannot be left alone in good conscience. You have a moral obligation to be less wrong: http://www.wrongbot.com/2011/02/27/stop-being-wrong-a-moral-...
Regardless of reach, I still don't believe attacking or embarrassing someone is the answer. My conscience is better off letting someone have a right to their own opinion (albeit a poor one), rather than attacking them for it. In other words, I'd rather choose to understand where their point of view is coming from and accept it, than to try and change it.
Everyone is welcome to have their opinions. When one attempts to act on those opinions in a way that's harmful to other people, one cannot but expect others to oppose.
Let's say I believe that three-year-olds can fly if only they're forced into a situation where they must do so in order to save their lives. It's a stupid opinion, but it's harmless if it's just a thought sitting in my head.
Now let's say I decide that I need to teach a bunch of three-year-olds to tap their innate flying ability by throwing them off a bridge. Is stopping me from doing so disrespectful of my opinion? Would that actually give you pause in stopping me?
Respecting someone's opinion is fine and dandy, but your inalienable right to your opinion stops when it starts motivating action involving others; at that point, the general rules regarding your rights when interacting with other people apply.