This line of argument to defend monopolies is the same line of argument against progressive taxation of high incomes. Just because those with trends excess use some small fraction of that excess to do good does not justify the means.

I have been close enough to billionaires and how they spend their money to not be fully impressed by such arguments.

And certainly the robber barons of the 2000s spend far less on the public good than when tax rates were higher and they used to fund universities, libraries, hospitals and the like.