I can't believe this didn't come to me sooner. I suppose, in my shock in the naivete of those who would promote the idea that it's not a big deal what people believe, my mind engaged in education mode. But I know many of these people I encounter don't really need an education. I know they're not actually as naive as they appear.
So, why do beliefs matter? Well, if one were to want to build a better airplane, beliefs about physics matter. The more accurately one understands physics, the more likely they will be able to build that better airplane. The same goes for other subject matters as well. In short, the better one understands reality, the more likely they will be able to build that better airplane.
What if instead we're trying to build is a better world? (Or a better society? Or however you wish to phrase this?) Why wouldn't the same rules apply? I see no reason why they would not. So, once again, the better understanding one has of reality, the more likely they will succeed at building that better world.
So if you still think that it's fine for people to believe what they want to believe, then I am left to assume one of two things:
a) You disagree with my assessment above that a better understanding of reality improves the odds of one being successful at engineering. If that's the case, I'd love to hear why.
b) You're not interested in building a better world. Well, that's your prerogative, not mine. That is probably all that needs to be said about this.