Why do we punish the people trying to help the underdog?

Things got very bad in the Central African Republic in 2013-14. The French (initially) and the African Union (later) sent in peacekeepers to try and stabilize the situation. While not widely reported in the United States, there was a very nasty tribal and sectarian bent to the mayhem, very much like that in neighboring South Sudan that same year. Some of the AU Soldiers were sympathetic to the grievances in some quarters, and turned a blind eye or worse. In some places, they were active participants. The abuses I heard about from my position in Africa at the time were worse than anything I have had in my career, and that is saying something. This was a very thorny problem for the French and the more professional AU contingents, as the chaos continued and even the mildest chiding was greeted with thinly veiled threats to pull out of their sectors by nations contributing forces.
Also noteworthy is the mercenary aspect, as AU nations are paid a premium for contributing manpower as compensation, and many times that goes directly into the pockets of the leaders of those nations. This is a lucrative industry in Africa, as there is no shortage of brush fires.

As for the whistle blower, there are powerful forces at work that are interested in keeping this quiet. There are similar problems of this nature in the AMISOM (Somalia) and Darfur missions as well.
Undoubtedly, the peacekeepers keep terrible situations from getting worse and have been somewhat successful at deescalating some of these conflicts, but many wear a stain on their honor as discipline breaks down in far-flung locales with little oversight.

We here in the USA don't even know the half of this story. It is bad. Really bad.

People don't want to know or hear about the good things, only the negative things.