Most likely this is because someone on the dating profile saw the persons profile, thought it was interesting enough to 'dox' the person. If people knew how li

Most likely this is because someone on the dating profile saw the persons profile, thought it was interesting enough to 'dox' the person. If people knew how little information is needed to get started they would be either terrified or amazed. First name + Location + Instagram profile and you are already off to a good start. And maybe there's a picture from some marathon you participated in, and they might have an online list of participants, narrow down to matching first names, then look them up on facebook. What facebook then sees mimics person A trying to find his new friend person B, which makes it natural to include this person on the other "do you know list"