[faeriechangling]

If vaccine safety can't be established by anything but time, than debate definitionally cannot inform us about the safety of vaccines. Vaccines can not only be unexpectedly dangerous in the long term, they can also theoretically be unexpectedly protective, and we can't know without waiting.

I've seen no evidence of /r/thenewnormal advancing scientific research in any way, and arguably they are having the effect of having amateurs direct research priorities due to phenomena like them promoting ivermectin leading to a surge in poisoning cases and thus scientific interest. The presence of "debate" does not nessecarily advance the scientific process, debate can be rhetorical sophistry that hardly achieves the same end as for instance peer review.

The best argument I can think of for allowing such communities is to put mainstream science in a position where they MUST respond to heterodox scientists or risk the public heeding their concerns and not getting vaccinated etc. etc. I don't think this is an incredibly convincing argument either, since it's a rather costly way to enforce sufficient scepticism, and it's disputable if it's nessecary.