Not sure why you are saying this is technically an awful image. Composition is a good ROT. Thing I would add is some more sharpness to the baboon. Only thing that would have been better for him is a head turn towards you. Overall, with the clean BG and getting him in the open - well done.
Basically because it is a very large crop and the detail is lacking, probably to much movement. I ran lots of rounds of selective sharpening on the baboon which made little difference.
I just whish the baboon had been a good deal closer, just because I have never seen this sort of behaviour before and doubt that many others have.