So, I divide things into two camps. I think one can hold an unpopular opinion about subjective things, and it's fine. I won't judge you for preferring tabs over spaces, even if I think you're wrong. I won't weigh that opinion against your other work either. It's like preferring sweet potato to apple pie. You're still wrong, but again it has no bearing on objective facts. :^)

When you're outspoken about an objective fact that has been proven out by a mountain of evidence like vaccines being safe, or the earth being round, that's when I become very skeptical of any of your other opinions.

The amish woodworker is an interesting question. I wouldn't judge him for being wrong about things outside of his domain as I'd assume ignorance instead of malice, but if he started popping off very wrong theories on the nature of oak vs pine I'd probably be leery.