Are there any real reasons for shareholder primacy to be controversial?

It's one of those things that every social ill in existence is consistently pinned on. Recently I read that it's an actual doctrine outlined by Milton Friedman. But was it ever different pre-Friedman? Isn't that the most obvious course of action if you own capital? And does it even make sense for a company not to follow that doctrine?

Please try to be clear, I'm a total layman!