I feel I need to expand on my reply to you, Underseer:
My defense of the "right" to an unsavory belief is wholly on principle. I don't mean for a moment to say that potentially harmful beliefs should be "tolerated" as in "we ought not do anything about it." I don't celebrate false beliefs, or even defend beliefs themselves - only a person's right to hold them.
My difference of opinion with you, or so I believe, lies in exactly what ought to be done about the fact of people holding potentially harmful beliefs.
I am not promoting blind, apathetic tolerance of bad ideas, but tolerance as a civil constraint. I very much support free speech - as a means of promoting good ideas and heaping censure on bad ones.
It's one thing to say that one does not have the right to their beliefs; it's quite another to try and back that up by any kind of practicable legal means.
In case none of this is coming across: I do not approve of someone sticking their fingers in their ears or intentionally blinding themselves to facts any more than you do.
What world do you live on? Most of the people on this planet can and do believe damn near anything they want.....flat earth, flying saucers, three-headed gods, and on and on it goes. Very few of us do not subscribe to beliefs, but a system of determining what appears to be the theory that is best supported by facts.