Seems likely, their stupidity functions as a safety mechanism. It's just like why elaborate government conspiracies fail: People are eventually stupid and untrustworthy, the more people involved, the greater the likelihood somebody fucks up hard. When you take a group that's already very poorly educated and lacks critical thinking, they're probably not going to do too hot in any form of sustained warfare.

Doesn't help that they think people who aren't far right are unarmed soy boys: There are plenty of moderates and liberals who are armed and can fight just fine.