I find this argument to be extremely ridiculous. They solved some math problems and published the results for free. No one asked them to do it, they weren't paid, and they don't owe anyone anything. Who exactly is exploited and excluded? The entire notion of open public information is that you can do anything you want with it, including build private systems. Is a baker "exploitative and exclusionary" for reading a recipe in a book and then turning around and selling that bread to customers, without sharing the recipe with the customers?