That's what they mean, those 50 acquaintances are your mutual connection, not those 20 each you've never met.

True, my bad. I guess I was thinking of it though in the context of a recommendation to connect based on a mutual connection, whereby you could easily come up with a list of 1000 people who I don't know but that one of my friends does, since the context was a social media platform and that's a common feature