I think GitHub should allow disabling PRs. I don't believe most big corporations are interested in dealing with fly-by contributions because it might make them look bad or be riddled with quality issues.

Also some projects like the Linux kernel are just mirrors and would be better off with that functionality disabled.

While that is true, I feel like it is irrelevant here since it seems like Okta definitely wants (and perhaps needs) the fixes. God only knows why GitHub still forces it on though. Early on it might've been some mechanism to encourage people to accept contributions to push the social coding aspect, but at this point I have no idea who this benefits, it mostly confuses people when a project doesn't accept PRs.

GitHub actually can natively mark a repo as a mirror (or could? I can’t find an example now, but they have always been rare). The book-with-bookmark icon before “user / repo” in the page header is replaced by a mirror-and-reflection-ish–looking thing, and the badge after it changes from “Public” to “Public mirror”. Unfortunately, forcing you into “social coding” (wait, is that no longer on the homepage?) takes priority, so that mark can only be given out by GitHub staff through manual intervention, and it doesn’t often happen.

Maybe the community should use less of github if github doesn't provide features the community finds useful.