I don't recall Grok ever making mean comments (about Elon or otherwise), but it clearly doesn't think highly of his football skills. The chain of thought shows that it interpreted the question as a joke.
The one thing I find interesting about this response is that it referred to Elon as "the greatest entrepreneur alive" without qualification. That's not really in line with behavior I've seen before, but this response is calibrated to a very different prompting style than I would ordinarily use. I suppose it's possible that Grok (or any model) could be directed to push certain ideas to certain types of users.