Open source projects like LLVM need to do this as it is one of those projects that is widely used in the software supply chain, on the level that needs protection from contributors who do not understand the code they are writing or cannot defend their changes.

There needs to be a label which designates such open source projects that is so important and adopted throughout the industry that not anyone can throw patches to it without understanding what it does, and why they need it.

This is why gcc and linux use mailing lists instead of github pull requests.

In the gcc/linux flow, convincing the rest of the mailing list to not ignore their message is the submitter's job.

In the github flow, keeping the "unresolved PR count" (displayed right beneath your project's title) low is the developers' job.