I haven't dug into it, cause I don't really care.. but I imagine that fb/meta tracks more than clicks. If I were them, I'd have js on the page that tracks your scrolling, and pays attention to the posts you 'hover' over for longer.

I bet that's just one of the ways they track behavior on their platform. So if you slow down to check out the ladies, I bet more show up, even if you don't click.