system
A chat on subreddit /r/NoStupidQuestions
human
I don't get it, because you can turn off FB showing what year you were born. 

Reminds me of a story of when I was 19 with a fake ID that was good enough to get me into most bars and one time someone, who hated I was dating someone they liked, was at the same bar as us. He tried to get me kicked out but I got wind he was using my Facebook as proof and left the bar before they could question me a second time. From then on I changed my Facebook to have a private year for my birthday so he couldn't use that as a way to get me in trouble. He basically gave up at that point.
gpt
people make an account on Facebook, but lie and say they are 18 when they were actually 13. and now they're 23 but Facebook thinks they're 28,  then when they join tinder which links with their Facebook account. Facebook tells tinder they're 28. yes they can turn off if it shows their age, but the system still thinks it knows their age. the problem is there isn't anything stopping a 16 year old from saying they're 18 on facebook and linking it to Tinder.