> If you equate people who are bad at their jobs with hobbyists, it implies that hobbyists are bad at what they do which is simply untrue. Many hobbyists are very very good at what they do

I see it as distinguishing between endeavors where being good is a requirement and those that are not. Of course there are many highly talented and skilled hobbyists but it’s not a requirement. It’s not even a requirement to want to get good at a hobby, though most probably do have some level of attainment in mind.