Worth noting that Musk apologised in his testimony which is a distinct change of tack from his actions prior to the trial.
Musk, in his position as a public figure and CEO of a number of major companies, really should know better than to fire of a dodgy comment like than in social media. He then chose to compound it by repeating the allegations (contrary to advice given by his advisors). I can understand he might be frustrated initially at Unsworth's comments, which were ill advised, but to make such a baseless comment as "pedo guy" and then follow it but by "I bet a signed dollar its true" and then be caught out by a reporter "stop protecting child rapists" over the course of months means he had time to think about his comment, carry out an investigation which proved it to be baseless, and still double and treble down on the original comment.
Unsworth's comments have to be seen as a spur of the moment comment during a TV interview during what must have been some of the highest emotional and mental stress imagninable. He was speaking from the viewpoint of someone that was working very long hours on a very stressful potential rescue where, even with the most optimistic viewpoint, they thought they might lose 2-3 kids if not more by bringing them out. Some of the people involved even worried that none of them might survive but thought they had to try something.
To me, if Musk had apologised after the first comment and said no more he might have walled away without any issue. To compound the original comment appears, to me anyway, to be a deliberate course of action.