I hate to devil's advocate this. But is the observed behavior of 'is this an outgoing link' the only practical way to defend against external bot advertising campaigns? Aside from Facebook obviously wanting you to pay them for advertising, how does any independent forum deal with this at scale without banning links?

So you have to pay a small amount of money to keep running your criminal enterprise? This would slightly raise the cost of doing business. Scams and banned goods already account for 10% of "Meta" revenues [1]. This move acknowledges that reality and creates a new rent-seeking behavior around it.

https://www.reuters.com/investigations/meta-is-earning-fortu...

"how does any independent forum deal with this at scale without banning links?"

By banning spammers and scammers. Facebook opts not to ban scammers, as it's a significant portion of their revenue, and the latest AI slop is very good for engagement.