Divine Knights of Bastok

so I saw this video and thought...why are people failing this mission?!

http://www.youtube.com/watch?v=TOc5cLXGV3Q

I haven't tried the fight yet myself...but come on! I've had promy runs more troublesome than this!
the NIN was just standing there waiting for clones...a thf could be chipping away at the crystal with Marksmanship during that time!
ppl keep saying AoE and charmed tanks killed them...at least that's what I hear mostly...
AoE wasn't being spammed like omgwtf! and charm...the Monk just pulled back a bit! plus it said in the annotations that it can be stunned...
I mean Jebus really...Bob freakin Jebus...