This is when co-mingling becomes actively dangerous. New members may (often, will) lack the necessary knowledge to identify core vs. fringe beliefs, to contextualize debates, to recognize insider "shorthand" for what it is, etc. They need (and are possibly even looking for) a useful education, not to become test subjects or disciples. They _cannot_ be engaging in useful research at this stage, even if this is what they wish to do (there are some unfortunate status-seeking behaviors that can come into play here).
Also coming with this scale are a crap-ton of meta discussions concerning basic community governance, including those around "how quickly do we have to kick out crackpots to keep them from recruiting here?" Those discussions _also_ shouldn't be co-mingled with the educational structure, although it's good for new folks to have some visibility into them and at least know that this sort of governance _exists_ in a tangible way (because if it's opaque, that thing you noted about crackpots playing victim becomes a LOT more effective).
This is all a huge amount of boring, tedious work, and... An awful lot of communities start in on it waaaay too late or don't bother at all. What if it stops being fun and exciting and everyone leaves? Of course, there are worse ways to go, but folks tend not to think about those until after they've happened.