IIRC, the word "Robot" itself comes from the Czech play "Rossum's Universal Robots[0]" and translates to slave, so the metaphor of class struggle was always there.
(Important to note that, just like in Do Androids Dream of Electric Sheep & Blade Runner, the 'robots' in R.U.R. are not mechanical devices but instead genetically engineered synthetic humans. That helps the metaphor a great deal: rather than being a pure 'other' whose behavior might be seen as a design error, it's simply a different breed or race of humans with different heredity that makes them convenient for othering, along with some argument about hereditary traits that supposedly make them more suited to hard labor.)
It's a made up word. If it translated to 'worker' he'd have just written 'worker' in Czech.
In all slavic languages, 'robot' is the base of the verb 'to work'. So, by the same means by which some people have decided to translate 'robot' as 'slave', it would be more accurate to translate it as 'worker'.