That’s only slightly more clear, since it just says what’s not happening. Does anyone know what is happening? Does it involve potential violations of law, or is it just the TOS?
Sexually explicit "meetings" wouldn't even be a particularly surprising use case, and 18 USC 2257 has a bunch of carve-outs for service providers.
My suspicion is that there was CSAM or similarly abhorrent content being broadcast in meetings. Unfortunately, this is a class of users which would be drawn to a service which promised anonymity and E2E encryption.
All things you don't want your company to be associated with so you don't name it.
If it would just have been things which are illegal but not that problematic like copyright violations or a bit of (legal, non forced) porn they might have spelled it out.
e.g. people which investigate forced porn stumbling over a forced porn site which uses your service
Gotta wonder if Mbone was also used for the really ugly stuff which is in fact very illegal.