Maybe a more constructive way to look at this would be that people simply do "dumb" things. In customer support where you only see those moments, it might not always seem that way, but dealing with people's simple mistakes is also educating them to do better next time.
People can be ignorant, lazy, not give a shit about the work they are doing, have poor learning ability and or skills, and cross their fingers, mashing buttons, hoping everything just works, and then expect everyone else around them to help them out of their screw ups.
If you've ever worked in CS, or known anyone that works in CS, you know that there are an absolute fucking shitload of these people. Often in roles they are unqualified for and with privileges and power no sane person would ever give them.
That's true. It's also true that AWS's IAM system is pretty complex and not incredibly well designed. AWS internally makes mistakes with it with some regularity.
Maybe a more constructive way to look at this would be that people simply do "dumb" things. In customer support where you only see those moments, it might not always seem that way, but dealing with people's simple mistakes is also educating them to do better next time.