Opinions based on insufficient information help immensely in determining whether we have sufficient information, and also raise awareness of important topics that we need more information on. These blog posts serve a very important role in the information exchange ecosystem and the whole world would be worse off if all these people held off until they're 99% certain. Nobody would be talking about climate change, about economy, about quantum gravity, about ancient civilizations, about prehistoric animal species, etc. etc. and so on.
People in the rationalist community don’t see it, because ironically they’re not rational enough. But they use the language and essay format to make it seem like they are.
I wrote in a sibling post that they like fascism because any dispute can be reduced to and solved by beating the counterpart to death with sticks.