But that wasn't my point. It's not that I think that Facebook or Google cannot scrape Fediverse platforms/instances, it's that even if they do, they cannot serve targeted ads based on our activity here.

This is another one of those things where Meta's claimed motivations for this don't seem to stack up.

How exactly are Meta supposed to serve "targeted ads" to me, @bloonface, if I am on finecity.social and not [whatever Meta's instance is]?

If I don't have an account on their service, and never visit their website, they have no opportunity to put a tracking cookie on my computer, no opportunity to serve an ad to me (other than directly messaging me, behaviour which would absolutely get them defedded instantly by anyone who is even close to being on the fence about their presence), no link between my finecity.social account and any Meta accounts I may have... what benefit do they obtain from this?

Bluntly - how is this dastardly plan of theirs actually physically supposed to work?

A lot of people seem to have ascribed omnipotent powers to Meta far beyond what they are actually technically capable of. They can't deliver you a tracking cookie or make your instance display a banner ad to you through ActivityPub, ffs.