Most Syrian rebel fighters hold extremist views similar to PISSI, even though they are enemies of PISSI.

This shows that defeating PISSI won't eliminate Salafi oppression from Syria. (There may be no way to do that, in the short term.) However, those groups might not want to attack outside Syria; it might be possible to make peace with them.

It will be hard to make peace in a way that includes them and the secular Kurds.