He isn't telling you what you can and can't eat. He's just exercising his right, as the person who paid for and owns the club, to decide what to sell and not sell. The supporters also have a perfect right to tell him to do one.
He seems motivated to do what he thinks is the right thing and this will likely be very much supported by young parents and young supporters who are more likely to have a vested interest in the climate change argument. Good luck to him.