Twitter doesn't consider themselves to be a social media platform and they are not listed in the social media category of the app stores.
He responded in a public. In which case, he's fair game for the public to respond back. Either on twitter or here, or anywhere else.
You seem to be making a huge deal about nothing. Your grandstanding in his defense has drawn way more attention to him (here at least) than the original tweet. If he really and truly doesn't want attention, maybe you should just let it go. On the other hand, if he does want attention then
@CupWizier was right all along.
BNM