I think it may not be much of an issue, Now that he has publicly proclaimed his win and proved our ignorance and stupidity, and taken his victory lap here, I doubt he will be back. Although now I posted this, If he is still reading the thread, he may just respond, but continue to be in denial and lacking any understanding of the word salad posted. however if that happend, it will likely be fleeting, as they tend to go away when they can't back up their claims, and verify the truth, although here the "Win" didn't seem like a success in court, but perhaps acknowledgement of another small and unrelated issue, that ultimately had no impact o the outcome.
TL;DR He likely wont be around much longer for ignore to matter, they usually slink away after they claim victory to a loss, not unlike their experiences in court.
EDIT: There is an ignore feature, go to your profile, and the Friends and Foe screen. Add to Foe, and you should be able to ignore