To answer that, The MMA Journalist has reached out to every Assembly member whose name isn't attached to the bill and asked for their stance on the matter. Not everyone has responded, and I don't expect them all to, but I will post the responses of those that do here.
First up: Assemblyman Michael Benedetto from the Bronx.
I believe mixed martial arts is a particularly brutal and dehumanizing sport. However, I believe New York is the only state in the country that retains a ban on this sport and that, therefore, it is foolish not to recognize and regulate it.