Workers of the world, unite. Nothing’s too good for the workers. You know what it means, instantly, when you see “worker” in a phrase like that – what kind of working people, exactly, is being addressed.
You know it doesn’t mean billionaires, even if they spend every waking hour in the office. It doesn’t mean people who own a string of buy-to-lets either, no matter how long they spend managing their property empire. Conversely, you can identify as working class in this sense even if you’re currently not actually doing any work but are on strike, or looking after small children, or even retired. Being a worker is more a virtuous state of mind than a socioeconomic definition, and like all feelings it doesn’t always make logical sense. But when wrapped inside a clear political ideology, somehow it works.