I can see the logic of "stop random adults from chatting up kids they like the looks of" and of "but of course allow communication between two mutuals".
But given what I know of the influencer attention economy and general adult/youth segregation since 80s helicopter parent exurbanism, it strikes me that "the only adult voices children will be exposed to are the particular petty celebrity charismatics who have succeeded at charming them into their retinue on a numbers game basis" is also not ideal and suggests failure modes
Even beyond sex stuff. Like, we have a whole folk legend about the Pied Piper, remember?
It's funny to me that you think it's to stop adults from talking to kids, because my first thought was that it's to stop kids from harassing adults in retaliation for them shipping Problematic Ships or w/e.
Like, an example I saw 2 days ago
Like, one benefit of tumblr shedding to twitter is that as this stuff gets worse I increasingly see a fairly quality share of one-time Buffy-and-Xena viewers not even try to address it but just grow and define their circle by holding it up for disdain, which that platform is better for