Because they're working but not in a way that is recognized by the government data which only recognizes formal labor for a proper employer.
I would go so far as to say that the employment rate is effectively always 95%+ for every population and that the only question is whether people are working in the formal economy, in school, informally working, caring, or doing any number of other activities that make up our human society.
I would go so far as to say that the employment rate is effectively always 95%+ for every population and that the only question is whether people are working in the formal economy, in school, informally working, caring, or doing any number of other activities that make up our human society.