Sure, that's why they should steal other people's work without any credit or consideration to their morals. Because it's a "fiduciary responsibility", this is totally fine.

This is a fiction. I'm not sure if it is pushed by corporate apologists, or by people trying to convince others the system is completely broken and must be destroyed (and replaced with system X).

An analysis of this claim:

https://www.nytimes.com/roomfordebate/2015/04/16/what-are-co...

In general, corporations are given a large leeway as to what is 'in the best interest of the coporation'. Fidiciuary duty basically means CEO's just can't run the company into the ground and spend all the cash on cocaine parties.