The premise of the question is an interesting one. I have to disagree with it though because I don't think that Miller's use of Salem is a distanced critique of McCarthyism. Rather, I think that both are very analgous to one another and Miller knows this. Both McCarthy and Salem both featured "legal" proceedings that were not authentic nor transparent, filled with false and forced "confessions" and replete with denials of personal freedom or institutional checks. At the same time, both sets of proceedings were meant to deny the fundamental problems in both social orders. The convenience of accusing people of being witches or Communists prevented a more indepth and reflective examination of how social practices need to be rethought and reconfigured. In the reactionary measures of both proceedings, Miller is arguing that there is little substitute for honest reflection and rumination. In both settings, Miller asserts a belief from Justice Brandeis in that "sunlight is the best disinfectant." Finally, Miller is able to suggest that both sets of justice miscarriages are at the hands of charismatic and self serving individuals. Abigail and McCarthy both are very skilled at rallying public interest in agendas that are highly devoted to self interest. In these details, I don't see Miller's use of Salem as a distance for his criticism of McCarthy and HUAC.