I think it's just "humanity" and self interest, not sure any given government form is immune to such things.
Historically when I see folks rise up to stop such things, they just mean get their own piece of the pie, or all of it. Humanity is very good at "problem solved, because it is ok when i do it".
This was a lot worse in the Soviet Union. The level of inequality there is hard to comprehend, where your personal essentials such as freedom to move or being able to defend yourself from violence highly depended on your "wealth", that is your standing in the "nomenklatura". Not to even mention actual wealth, like having a car or real estate.
And it's not like it wasn't exactly the same under monarchy. Even with a straight arrow like Guizot (the straightest arrow of any French government ever probably) as a prime minister, corruption seep deep once people in power can stay in power for as long as they wish.
