I was in total agreement with him actually. You've provided little to show your argument that Blomkamp is unsuited to Halo. Landfall was and still as an absolute masterpiece, and district 9 definitely retains some of its look from its halo origination. (Blomkamp used assets and designs from the initial failed halo project) along with it being a solid movie.
You've said the gritty style doesn't suit Halo, but thats basically the descriptor for Halo 3 ODST and in my opinion Halo 2. Halo 2 was street level grit in the first few levels, and when they got to the stuff with the flood that was some serious gritty horror esque shit.
Lastly even if you don't agree with Juan don't reduce yourself to throwing insults. Keep it clean man, you do HaloGaf a disservice by being a dick for no reason.
I'm not going to argue with people who think walking around Mombasa as an ODST is "gritty" and in any way comparable to shooting your action scenes from a shaky cam on a gun and where whole sequences are shot handheld.
The Jenkins cam is novel in that it's the only "found footage" sequence in the entire franchise, not because it's a common stylistic device.