Re: “ISIS has nothing to do with Islam”.
Peace Jack Sparrow
You are right that is what the average ISIS member will say … And you are right it is hard to base whose version of Islam is true on say so … The only true versions that should be considered orthodox and true are those that are supported by scholars who have the license to deem a given activity allowed or impermissible … A good intention alone cannot be the means to ascertain truth of authenticity of a faith system … What needs to be established is which understandings are taking in to account the widest traditions and fuller context.
What is problematic in your argument is that you are asking to not only entertain a gross minority i.e. Less than 0.01% of the Muslims as legitimate but also asking us to place the common average ISIS member’s sincerity as a qualifier for the truth of the faith over the true license given to the scholars of the Muslim world by their teachers.