If a politician or a leading business figure said "I think latinos are lazy and worthless. I'm not going to debate that, it's just a personal opinion", would you still say that no-one would have a right to ask them to justify the statement or hold them to account?

No, because I hold the rights of races of people not to be discriminated or slandered against far, far more important than the right of video games to be considered art. Calling a race of people lazy promotes racism and actually affects people's lives. Whether video games are art is mostly an academic question. That's the difference.

I don't think journalists should have to answer questions on any topic that comes up. He clearly didn't know much about video games and he was happy with the art that he knew. People who think video games are art have a right to reply, but not a right to expect him to debate it with them.