It might be easier to reach the conspiracy/cult believers if we could say ‘look, it’s not that you’re stupid’, but it seems like this article is suggesting the rest of the sentence is ‘it’s just that you’re bad at thinking’

This is why I personally don’t like all the critical thinking advice online. None of it actually helps a person think better. Being aware of your own biases, for example, doesn’t automatically make anyone better at critical reasoning.