Though I would argue that the explanation requiring the fewest assumptions is not that Ma was being calculating and strategic, but that he just got cocky and said something dumb in the moment. He let all the global feting of his rise from schoolteacher to China's richest man go to his head, made an all-too-human mistake, and said something inadvisable.

He may even have been trying to defend the CCP in that moment, trying to communicate to US audiences that the CCP doesn't need to be feared because it's not scary, and thus he himself didn't fear it. But Xi and the powers that be interpreted it differently, and disappeared him. Which is always a risk in that system, but not in liberal democracies.