IMHO the best point made so far, in questioning the USAF intercept or more pointedly, in arguing that it was in one or more ways improper, is to note the terrible legacy of the Vincennes incident. Which was years ago yet still is a prime factor.
A lesser factor is that other airline operators have, according to the interpretations of flight track data made by others, flown the same, similar, or even more attention-attracting routes without action by the U.S. This cuts both ways, though.
First, those other operators, isn't it clear that they are not standing relative to the U.S. in the confrontational if not adversarial posture that Iran's chief local operator holds? Meaning that the deconfliction processes ostensibly devoted to U.S.-Russia air operations very easily could have been adapted so as to facilitate and enhance assurances about those flights. Mahan, in other words, isn't exactly on the same speaking terms as the other operators.
But second, as noted previously, it's a long-standing conflict zone. Other operators have flown quite comparable routes without difficulty, as far as anyone knows. Mahan knows it is not regarded as the same as those operators - regardless of whose side you take as between the U.S. and Iran, after the Solemani killing, the missile strikes by Iran, and the shooting down of the Ukrainian flight, the fact of anomisity and distrust is . . . a fact.
So if you are flying the Mahan aircraft, shouldn't you be more on guard and anticipating a possible intercept, not just as nominally professional as the other operators - and even more stable at the controls so as not to conduct a sudden evasive manuever?
If, on the other hand, facts emerge that the USAF aircraft approached in unusual, erratic or otherwise threatening ways outside ordinary visual inspection approaches, that would change the facts, considerably.
Might as well go all the way out on the limb: today is the date Iran had committed to delivering the recorders from Ukrainian Flight 752 to the French authorities, per their statement at a recent ICAO Council meeting. If the U.S. decided to conduct a gratuitous, and/or significantly disproportional intercept chiefly or even largely just as provocation for provocation's sake, and the recorders don't get delivered as a result, I'll turn my sarcastic and sometimes valid posts in Washington's direction. Incompetence is a mortal sin.