I believe that it is known that his basic CA approach is not relativistically correct, but I’m not sure. But (even) more fundamentally, there are plenty of ways to reproduce something that sort of resembles some of the patterns of reality that we already know. It means very little. It’s when something deeper is captured that you can make predictions, and there is nothing like that so far in this approach. In any case, of course he should be left alone to fiddle around all he wants. I don’t think there is any chance, in his case, of criticism cowing him to a degree that he actually changes his mind about the usefulness of his ideas.