So..

if the engineering leadership said, this is not a good idea. Management said, it saves money.

Engineering failed to convince management. Management didn't have the understanding that it was a bad idea.

It is now, no one's fault?

If management merely takes the advice of engineers ( and other who specialize in the things that they do not ), and they choose to ignore it because they do not understand the things they do not specialize in. I believe it's a reasonable to assume that management is more at fault than engineering ( I'm not sure they're is a situation here where any party is fault less )

Management isn't going to question things, even with engineering warning them it's a problem every day.

Management likes hearing things they like, and simply don't hear things they don't like. Then act surprised about it when it becomes public.

Hippocratic oath for engineers is irrelevant, correct. But management does not take the advice of engineers. As I said, the engineers wanted to do proper engineering, but management wanted to save a buck, so they instructed engineering to fudge a cheap solution.

Its very common.

That's like saying burglars who break windows demonstrate the irrelevancy of door locks.