There’s like 1000 reasons why the domain could be used. (For example you wouldn’t want 1M phones destroying a website because it became viral on WhatsApp, hence a caching layer is probably needed)
I don’t work at Facebook on this specific system that handles link previews so I have no idea of the details.
The fact is that if they send a request containing the link I previewed which is tied to my IP which connects to my Facebook account then they can 100% correlate that information and figure it out.
Are they doing that? Maybe, maybe not. I don’t work there. But they can if they want to so it all comes down to trust. Do you trust Meta?
