From the link provided by
Richard Hollywood
SAA/Hezbollah keep rolling through South Aleppo where they're liberating towns and villages daily now.
it was officially declared by isis leadership that killing traitors, heretics, and pagans takes precedence over dealing with christians and jews(who are to be treated according to islamic law). This is why hezbollah and other shia mercenaries and jihadis are considered a greater enemy than israel. There's both strategic and religious reasons for this policy, like israel and isis having mutual enemies(assad, iran, hezbollah) and islamic law which instructs christians and jews must be treated better than heretics(shia) and pagans(alawites).
It may be a moot point since heretics are slated to be killed too per the policy you describe, but - what makes Alawites pagans instead of heretics?
Alawites are considered to be more heretical than Shias because they believe in a lot of strange stuff, like reincarnation(including being reincarnated into animals) and that women don't have souls. They have a different creation story, that they were stars cast out of heaven. They believe there many living manifestations of god including Jesus, Adam, Mohammed, Ali and a handful of ancient Greeks and Persians. Many Sunnis and Shias don't consider them to be actual Muslims.
SAA/Hezbollah have cut the M5 Highway that goes from Aleppo into the hinterland down towards Homs and Hama.