Well, yeah people call them stupid because they have the most access to facts out of all humans throughout history and yet work hardest to reject ALL of them except those they want to believe.
And I don’t think most people were all that quick to dismiss these people’s pain at first, in fact a lot of us have felt it firsthand. It’s just really hard to feel sorry for people who are proudly bigoted, hateful, and willfully ignorant.
You’re right, it’s not helpful to call them stupid and dismiss their views, but it’s honestly like we have no choice. How do you help and have empathy for people who would make your friends’ existence illegal? How can you take seriously someone who constantly screams about problems that don’t really exist, and are solely based on fearing people who have no interest in bothering them?