I agree about the transparency when it comes to a business's activity: its goods and services.

But a business's ownership is about the privacy of its owners/stock holders - which are regular people. Saying their privacy is "morally dubious and self serving" is akin to saying regular people's need for privacy is morally dubious and self serving. Is the old anti-anonymity argument of "if you're all legit, what do you have to hide?!"

There is an argument to be made here though when said owner is another corporate entity - that is not a person so maybe it doesn't deserve any privacy.