Here's my theory on how Facebook can be telling the truth here: Your Tinder/Grindr matches are people in your local area. Your Facebook social graph contains p

Here's my theory on how Facebook can be telling the truth here: Your Tinder/Grindr matches are people in your local area. Your Facebook social graph contains people in your local area, even ones you don't know, through your local friends. The chances of one or several Tinder matches eventually intersecting with your Facebook graph are significant. When this happens, people interpret it as a deliberate act, not just a coincidence. If you use Tinder in an area which does not contain any of your friends, and people from that area subsequently show up, and have no connection to any of your friends, that would be a lot more suspicious.