"What is it that makes them look after each other, even defending what is morally wrong in some cases (so I'm led to believe)?"
Prudie, when I was in my old football team we looked after each other, as we tend to do at work these days. Why would the craft be any different?
Lots of people enjoy meteoric rises in workplaces, and ass-kissing and sycophancy can play a big part, as can learning all the right buzzwords and being so PC it hurts. I haver seen some of the biggest idiots promoted many times, and it wasn't through hard work or ability. As I said, HR should be your port of call if you know of nefarious dealings in work.
As for moral wrongdoings; unless you can cite an example then this is just another of the rumours that you seem to think proves the truth.