yer read this one http://warhammer40k.wikia.com/wiki/Raptors or IA10 that other one is very dumb down.
No where does it say the Inquisition is part of the Chapter, but that they are working hand in hand. Strange yes but I would say less so then allowing daemon possession on space marines. There are a few chapter that work with the Inquisition Son of Medusa, Minotaurs and the Red Hunters just to name a few.
And where is everyone getting this Anit-gov. thing from nowhere in the fluff does it state that. The fluff really just breaks down to these guys are the Catachans of the Space Marines.