All jobs are equal but some jobs are more equal than others.
On a more serious note:
Of course all labor requires some level of basic human capability and as such must pay a living wage. But there is very much a distinction you can draw, based on the amount of training required to perform a job accurately and safely without supervision, and how much background knowledge is required to go above and beyond the daily work, e.g. to respond to emergencies or to further develop e is ting procedures.
Because it's a convenient way to talk about work. The collective of all who speak the language drives the process of word creation and definition and benefits from it.
The fact that companies pay workers too little is independent from this. I also don't think that the word itself is "weaponized" so to speak.