I understand he wants to deflect liability from his platform, but I guess I have to concede that it seems like a legitimate defense. We allow the stock market to exist even though insider trading can happen and it's (I think?) not Nasdaq's or NYSE's responsibility to pursue that. We have a legal system for that.

I think there is still the debate to be had whether prediction market enable too much criminal activity and insider trading compared to traditional stock markets and therefore need to be limited for pragmatic reasons (i.e. the legal system can't keep up), but that's a different discussion.