I fail to see the moral problem with being able to write a book that millions or even billions of people can enjoy. To me that's a feature, not a bug.
Work on your reading comprehension. The comment you're replying to specifically said they were not impugning the morality of artists or fund managers.
Making great art is wonderful, but it's certainly not "work" the same way that digging a ditch or answering tech support calls is.
Of course that is a feature, but at this point I have to suspect that you're willfully ignoring the point.
The moral problems begin when writing that book gives you extraordinary power beyond what is healthy for society (which is extremely rare for authors, of course; the discussion isn't really about authors, you just invoked them in an attempt to conjure a moral shield for the people who are the real problem).
And again, even that in itself is still not a moral failing of the individual. It's primarily a failure of the system in which the individual operates.
It does become a moral failing of the individual if the individual uses that power to perpetuate the system.