The calculus changes for someone like Musk, who is not a troll to a large fraction of the population. In that case, it's beneficial to post something like the GGP because it signals to other people two things: first, you're not alone in disliking this person. Second, it's okay to express that opinion. That second one is important since there is a fine line between ignoring something you don't like and self-censorship out of fear of reprisal.
So, while I agree that you should ignore nobody trolls, I DO NOT think you should ignore famous, politically/economically relevant trolls. It's an act that comes with some risk, and is therefore courageous and admirable.