Another way to see it is that if you criticize repeatedly somebody, and have being asked amicably to join him/her to talk about that, it would be polite at leas

Another way to see it is that if you criticize repeatedly somebody, and have being asked amicably to join him/her to talk about that, it would be polite at least to accept to hear his/her version of the history. Don't even need to join him, could simply have a email conversation Musk claimed to be unfairly treated, and asking to be allowed to explain their own version of the facts in private is not unreasonable. The professor may discover that was missing some relevant facts, or find a different valuable perspective of the history. He could also address this critics directly to Musk and defend his opinion. Both are adults