Just finished the game, hoping somebody can clear up the ending for me....

They were already fighting the CIA in a civil war before your squad came over, so I don't think they were interested in being friendly to another bunch of armed American soldiers. I think.

Thanks for the reply...

It's not like the other guys in your squad didn't have radios to communicate with the 33rd, find out what the hell was really going on. Seems kinda dumb. The game wasn't that great I was really hoping for an awesome ending...kinda cliche and significant plot hole.

(not normally a hater, but this story didn't really deserve the hype it got).

The 33rd also split into 2 factions I believe.

did they split? then there was the whole thing about the CIA trying to cover up what happened...but they never really explained what happened...like stuff was really f'd up...but WHY?

I assume they split as we saw executed soldiers

At first, they attacked you because they thought you were C.I.A. They were on edge because, as Radioman said, there was an end to the ceasefire between the 33rd and the insurgents (insurgents being on the C.I.A.'s side). Later, they're attacking you because of your gratuitous use of white phosphorus.

I think its supposed to be ambiguous as to what was real and what wasn't.