It's fine to be against cars and not use them. But then to be obsessed about it to the point you end up preaching it like hardcore vegans, it gets obnoxious and is counterproductive. The reason for the connection to flat earth is because there are plenty of valid conspiracy theories to be analysed (oil companies doing suspicious shit) and having seen multiple posts about how roads are not meant to exists indicates the early stages of a warped worldview. And i sont just mean "the current road structures are bad", but rather it being porttayed as unnatural and therefore bad. Combining these factors makes me think these anti car communities are headed in that direction. But idk enough about it to know if it will happen, its just based on loose snippets i've seen from these communities.