You seem to have a serious problem with a complete lack of understanding of the US Armed Forces. It's like you never heard of the Uniform Code of Military Justice, the Laws of Land Warfare, or most importantly the Status of Forces Agreements.
All US military members are subject to the UCMJ and 99% of all personnel abide by it without problems. Most of the 1% get nailed on minor infractions but ones which have to be punished to uphold good order (e.g. AWOL, missing formation, DWI, etc.) Those who violate it to the level of courts martial rarely get a pass; they will be found guilty of something. The reasons are that first (since Miranda) the accused is read his rights under Article 31 UCMJ. He may be question with or without a lawyer (his choice). If things are nasty, he can either opt for Article 15 (non-judicial punishment) or a court martial. If that is so it may then move on to an Article 32 (equivalent to a pre-trial hearing to determine if evidence is present or if the charges warrant, and what type -- summary, special or general -- in order of severity of the crime and the commensurate punishment.) If it goes that far, it's rare that the accused beats the rap.
No commander EVER wants to get nailed for having GCM crimes carried out on his watch or worse be found out for having covered them up. This gleeful search for "Gotcha" criminality seems to ignore that and the overall level of high discipline in the US Army. (The ROKA is notorious, like many Asian armies, for beating the hell out of anyone who makes an error, and even killing a few troops. We don''t do that. Even the worst hazing incidents the US military had were both much less and expected by nearly all of the pre-PC inductees to become "one of the boys".)
SOFA is carried out between the commanders, not the press and not the troops and the population. If there is no push for a SOFA handover of the "guilty" parties, it's more likely that commanders have seen the accident for what it was and want to move on. Lefties in the press are more likely to keep this open. (Case in point: while there are numerous incidents that come out of the DPRK about shooting peasants or wrong-thinkers, where's the outcry from these same pressies on that?)