I believe that advertisers are leaving Twitter not due to nudity, but:

1. being associated with hate speech (companies don't care, they just don't want the association, they will fund hate groups behind everyone if it gets them lower taxes)
2. Musk's amazing engineering skills that breaks the site every Tuesday. Companies don't invest in countries that constantly have regime changes (but they'd definitely move into long term authoritarian countries that they can bribe and monopolize)

Threads' aversion of nudity? Most probably so that their app is approved in conservative countries. That's what Netflix and HBO did.

the same author has been writing about how NSFW content could make or break social media platforms, so I'm assuming he's just continuing from that.

I dislike that he completely glossed over the fact that there's a goddamn option on Bluesky to hide / show contents from political hate group! (Why the hell are they even allowed on Bluesky in the first place?!)