You just have to take the core lessons and try and critically look at what has branched out from them, I for example, interpret Taxation and Welfare policy as thought by Jesus to prohibit Welfare without work in it, and to be a proponent of progressive taxation which obviously makes me Unchristian to both lefty and righty Christians
Yes, ISIS is just an 'Arab Liberation phase' run by insane people. There is a concurrent Arab Liberation phase which would ideally like a peaceful settlement but also advocates war more often as time goes on. The problem is the second can unwillingly feed the first and is not wholly blameless.
Telling your son to fight against external oppressors is fine, but not when the only successful reference point he has is ISIS, because then he'll join ISIS basically.