Shareholders have limited liability. Management does not.

Management evolved language of avoiding responsibility. For example, instead of saying "use cheaper parts" they'll say "we need to focus on better use of our financial resources for increasing shareholder value". No court can pin them down for telling designers to use cheap parts, but the designers get the message. And if the designers don't get it, lower management will tell them in plain language. That shift the blame onto lower ranks while the top management is laughing all the way to the bank and move on to another high-paying job.

To commit criminal fraud with impunity?

Kind of, yes. The legal purpose of a corporate structure is that the corporation is a liability shield for the people in it.

It's to provide limited financial liability for the shareholders; the actual employees don't get any. And it has nothing to do with criminal liability.