I do have some experience, and while I certainly won't argue they're perfect, my observation has been that they're more than capable of delivering conclusions that reflect negatively on an organization. Dismissing their conclusions out-of-hand in favor of an alternative theory with no evidence feels like just believing what you want to believe.
> alternative theory with no evidence
This is a straw man.
>Dismissing their conclusions out-of-hand in favor of an alternative theory with no evidence feels like just believing what you want to believe.
Of course. I've also seen them first-hand nearly ruin multiple careers and marriages over allegations that were easily disproven at the onset of the investigation (Person wasn't even on base when incident allegedly occurred in this case).
By the time the investigations had cleared the accused of wrongdoing they were already passed up for a promotion and nearly ready to retire after 4 years of needless investigation. Part of the 'punishment' is the investigation itself. In my experience OIGs are political beasts because they're made of up humans which are inherently tribal/political.
I was saying nothing to the veracity of alternative theory.