They said it's the purpose of the patent system, not the real-world effect. It's very important to remind people of this purpose. Because people (especially lawyers) keep pushing this concept that ownership on a patented idea is some kind of natural right being protected by law. Which is completely opposite to reality, and part of what leads to the system being warped in the way you complain about.
Have a look at the original Gore membrane patent: https://patents.google.com/patent/US4194041A/en
It's very clear, detailed and reproducible.
And since we are on HN, here a bit on the software side: IBM original arithmetic coding patent.
https://patents.google.com/patent/US4905297A/en
Perhaps it something that should not have been patented, but it's fully disclosed and reproducible.