As an employer that does the same thing as the person who wrote the article; I do, of course, look at the seriousness of whatever is on that Github profile.
I am usually easily able to tell if it is a half-baked project for some hobby-thing or active participation in e.g. a well known piece of open source software.
Someone who does this, is likely also skilled enough to separate those things. I don't only look at the user's own repos but also at contributions/comments etc. to others.
And just as the author, I too experience more often than not that people have NO idea how to set the level for own experience.