All this "insulting the prophet etc" is wearing a bit thin? Don't they think they're insulting our intelligence by spouting their nonsense?

If what they believe said that coal is White, I suppose they'd believe that and threaten dire consequences on anyone who said anything differently?

As to people "returning" from a source of radical fanaticism, rather than bothering gathering "intelligence", the best way out is to say "You went there, stay there, you're not coming back here".