I realize that. But independently of any PDF arguments, Iran has Sunni allies in Afghanistan, in particular among the Persian-speaking Tajiks. In Herat province, which to Iran is the most important area of Afghanistan, Iran never relied on any Shias but on Ismail Khan's Sunni Tajiks (or Persians, actually). I believe it's important to integrate this aspect in analyses of relations between Iran and Afghanistan. You specified that Iran wouldn't have reason to intervene as long as Shia Hazaras are safe, which is correct indeed. Likewise, the same holds true of Sunni Tajiks and in particular's Iran's friends among them. If they are oppressed, Iran would be just as likely to try and put a stop to it as in the case of the Shias.