Then clearly you would be ranked very low by something like this. I think that is the whole point of this: tell the people who have solid commit history from those who don't.
But the ranking is not reflective of actual skills. That's the critique. Aside from very frequent open source contributors (and I think these people are the minority of devs), devs will tend to be "profiled" by this tool according to the dot scripts, university projects, Advent of Code, or other half-hearted projects they happen to have put on their Github. (Maybe I'm just projecting...)
The issue isn't that not everyone has a Github presence, the issue is that for most people their Github presence is somewhat unrepresentative of their actual job skills.
The issue isn't that not everyone has a Github presence, the issue is that for most people their Github presence is somewhat unrepresentative of their actual job skills.