Also change my mind is kinda rigged against the challenger because he comes there ready with statistics, all the data you could want and he's basically debating bystanders who decide to debate him on a whim (at least that's what it's made out to be, only watched like one or two of them, correct me if I'm wrong.)
I usually agree with him even, but it's much easier to debate someone when you're actually prepared and come to the place with the intention to debate. It's very easy to make your opponent sound stupid if you're prepared to debate subject X and they are just a random person passing by who sees your "provocative" stand.
He also seems to pick pretty safe subjects like "two genders" and "rape culture", both of which are stupid subjects to begin with and shouldn't even really be up for debate imo.
However, he's pretty smart in the way he sets the whole thing up, he's prepared, he puts up a somewhat provocative sign that dares people to challenge him, so the people he "lures" in are already emotionally invested in the argument, which is bad for them.