Its intended purpose is to help make it easier to identify victims of human trafficking.
So a guy finds a way to counteract the way that underaged girls are disguised as adults so they can be "rented out" by cruel and hateful men...and he's evil.
Well, considering the ongoing exposure of abusers and rapists in prominent and powerful positions, color me unsurprised that the SJWs are freaking the hell out that someone has made it that much easier to help the victims.