Why insert a gratuitous "alleged"?

Interesting point by Tribe.

When I saw that, my first thought was that the Court might want to address when this question gets resolved. Courts are sometimes less concerned with the answer to a question than they are to when that question is answered, or who answers that question. So when I saw the alleged, I thought that one or more of the Justices wanted to make a legal point that turned on how an allegation (or assertion) of official acts immunity gets actually established at trial. Perhaps a point that an allegation isn't enough to stop the trial based on immunity, and that a judge doesn't get to make the call whether something is an "official act" or not that should be immune, but that it could be asserted at trial as an affirmative defense for the jury to consider.