The answer, again, is simple.
Either be better than the rest and guarantee the work or get another job. If you don't like the terms offered by your employer, go get another job with terms you like.
Even if that is true at the individual level (which I think it isn't totally), at the level of a nation or society the fact is that we need people doing these jobs, so no matter how hard everyone works there will always be people who finish at the bottom and have to work these jobs and in these conditions.
So with that being said, do you accept that your view here is driven by your lack of human empathy?
It would be much quicker just to agree and acknowledge that than go round in circles attempting to make other rational arguments.