This is vibe-based, but I think the Rationalists get more vitriol than they deserve. Upon reflecting, my hypothesis for this is threefold:
1. They are a community—they have an in-group, and if you are not one of them you are by-definition in the out-group. People tend not to like being in other peoples' out-groups.
2. They have unusual opinions and are open about them. People tend not to like people who express opinions different than their own.
3. They're nerds. Whatever has historically caused nerds to be bullied/ostracized, they probably have.
1. They are a community—they have an in-group, and if you are not one of them you are by-definition in the out-group. People tend not to like being in other peoples' out-groups.
2. They have unusual opinions and are open about them. People tend not to like people who express opinions different than their own.
3. They're nerds. Whatever has historically caused nerds to be bullied/ostracized, they probably have.