It's kind of odd that GitHub is asking people to pull an image from a Docker account that most people won't recognize (admiralawkbar/super-linter), as opposed to an official GitHub one.
admiralawkbar accounts for 80% of the commits in the repository and over 98% of the code churn. I'm guessing this was a side project of his (Lucas Gravley aka admiralawkbar) and the docker image was just something that was overlooked when it became an officially advertised GitHub repo.
But since its release, you still can't do public pulls: https://github.community/t/docker-pull-from-public-github-pa...