They're enabling chats with minors and selling their clothes, plus facilitating other transactions on what sounds like a gross version of Only Fans. Plus there's what the adults are saying to the kids, which is actionable in and of itself...

They're not enabling chats with the minors. The minors aren't the account holders. If adults are selling their kids' used clothing, that's certainly gross but almost certainly not a violation of the ToS. Most of the grossest discussion from the NYT article is between the creeps on Telegram, not creeps saying creepy things to actual minors on FB.

I think the behavior described in the Times piece is disgusting (especially the Telegram conversations), and I think the parents are most definitely not protecting their kids. But it's hard to see how any of that is a violation of FB/IG TOS....or even how you would draft a TOS that could address this. If an account draws a gross "fan base," that's not a justification to ban the account; and if the gross "fan base" isn't doing anything that itself violates the TOS on the site, you can't ban the fan base just because they're saying gross things on another site.

I would rather they not censor valid speech. However, as we've seen, the tech companies are very willing to put their thumbs on the scales so as to advance a particular political worldview.

Then why this post? If you don't think FB/IG ought to censor, why are you pointing out that they're not censoring these adults - or the adults they communicate with? And if you think they ought to censor, why don't they get to choose what they want to censor or not? After all, it's their site....