There's a difference between putting on a mask of citizenship because it's profitable and actually caring about the world beyond the size of one's wallet. Confusing the two requires confusing the meaning of "their own interests".
Is there, though? Maybe I'm just cynical, but I don't believe in the idea of "trusting" a corporation at all, because their default behavior (especially for larger companies) is to only care about the bottom line. Once you accept that everything a company does is for their own benefit (even if their actions happen to also benefit others) and learn to take each action at face value, I find it easier to evaluate the consequences of those actions.
The idea of trusting an entity that is designed to try to take your money seems silly and futile to me.
Your argument here is tautological. I'm not saying that one should never use that analytical model, just that there are other ways to do things.
Companies don't act on their own or have beliefs. Only the people that make them up do. The company does need to turn enough profit to sustain itself, but beyond that, it's in large part up to the people who make it up. One of the thorniest problems in investing, for example, is the principle-agent problem, where people act in their own interests.
In America, that's mainly thought about as CEOs and executives serving themselves, not investors. But that's a cultural thing. In Gemany, companies are much more focused on all sorts of stakeholders. That's also often true in America with small and medium businesses, especially ones that are family owned.
Companies are hopefully designed to do whatever the stakeholders want them to do. Sometimes that's serving somebody's rapacious greed. Sometimes it isn't.