That's a good question ukanonymous.
The press call them extremists, non muslims call them extremist even other muslims call them extremist.
Extremist means someone who has extreme views or actions that today's society won't accept. They aren't actually extreme in a religious way as they are following the book. 'We' don't like what they are doing so say it's extreme. Other religions who's followers go exactly by the book are called devout. So religious wise they are devout and by society standard extreme, if that all makes sense.
The verses you gave -I think-refer to war itself rather than jihad as you mentioned in your first post.
A more appropriate verse for why they go to another place and join in war is this
.those who leave their homes for the cause of Allah, and are then slain or die, Allah will, surely, provide for them a goodly provision...
From what I've read, if anyone fights in the name of Allah they get a special place in 'heaven'