Personally, I could list off the top of my head several likely candidates for the top editors and IDEs, but I don't have anything useful to say about most of them, because I don't use them. I fully expect the author is in the exact same position.

You're absolutely right that the list is not comprehensive, and it's probably the author's own personal preferences. But if he uses mostly those editors, what's he to do? Just list off a few more editors/IDEs with no links to any useful resources, when the whole point of the repo is to have actual resources you can read? How would having a header saying "IntelliJ" or "XCode" or "Visual Studio" make that list better? How would just adding a random link for some blog post about any of those help, if the list's author can't vouch for their validity?

It's overall just best to put in what you know, and leave the rest to PRs.