Have you ever tried to maintain a popular OS project on Github? Github issues feel great until you start using them at scale, and then they start to fall apart without some structure. This is especially pronounced in open source where many issues come from people who aren't familiar with what information you need in an issue to quickly resolve it.
I don't think the authors are requesting that this be made mandatory for all repos, but instead they just want the option to set up rules for repos they maintain. As someone giving up their free time to offer software for the rest of us, it seems only fair to let them set the rules about what they need before they can resolve an issue.
The biggest issue I see OSS maintainers running into is that they likely aren't the voice that Github listens to most anymore. If they can get some companies that pay for Github Enterprise to sign their letter as well that would likely help prioritize these features.