Many trips around the sun ago, I had the same feeling when I found sites like that. I quickly realised I didn't like reading PDFs or much enjoy reading from a Kindle.
When I published my first book I read Facebook threads where my colleagues were reading and passing on my book. I had an epiphany.
I use Kindle, libraries and charity shops to find new authors. But once I find them, I buy the book full price. And if it's brilliant, I buy copies for friends and family. At least, those who would appreciate it.
Why wouldn't I want a brilliant author to make money and be encouraged to write more?