I think that strengthens the point, don't you? Deep blue could beat humans a long time ago, and it's still the case that computers don't need humans to play chess, and play it better than humans do.
> and it's still the case that computers don't need humans to play chess,
Sure, I guess
> and play it better than humans do.
In the sense that they can beat humans in a 1v1, yes.
But none of that is relevant to the original claim, which is that a human in the loop makes a computer play worse--i.e., that human+computer is worse than computer alone. This claim is false, as the ICCF championship demonstrates each year.