what is the difference between traditionalist and modernized Islam?

You dont seem to really understand the problem. For the most part the radical islam we are seeing is a new type called salafiism. They claim to be following an orthodox, puritanical path, but their brutality is generally unsupported by the recorded history of islamic countries. Historically speaking islam wasnt exactly pacifist, but they mostly left jews and christians alone, and encouraged the arts and sciences. The terrorists are Quranic literalists.

If you want a western comparison. Imagine if jews suddenly developed a sect that believed the old testament word for word was exactly the way god wanted us to live in 2018.

really horrible slightly less horrible

Nothing