I spent (so far) 30 months in Iraq and never ever have I just stumbled across a guy butt punching a little boy. Not to say that it doesnt go on out there because it does, but even in the Iraqi culture gay/molestation is looked down upon by 90% or more of the population. That being said im sure if you DID come across this they would stop immiediatly and be more embarrased then anything. They do have emotions like other people (as much as I would disagree sometimes.) If they didnt stop I would firmly place my buttstock on thier forehead. Sounds like your buddy is being fed some typical "know it all" bullshit.
Tell him to keep his head down, follow his good NCO's lead, never ever second guess himself, and watch his buddies back because they will watch his. Also ask as many questions as he can think of to the unit he is replacing such as local customs, Enemy TTP's, and the chow schedual on his FOB/ Patrol Base