Seriously.
If you're an author, do you know how much it costs to have your book distributed, for free, via NetGalley? The answer is anywhere from $700 to $1500.
It costs anywhere from $1500 to $6000 to have an "Open Access" scientific paper published.
As an author, I love to see my stuff available on free platforms. To me, there's no downside. I've even paid open access fees out of pocket.