Earlier quoted context omitted.
Some of it has to do with the perceived righteousness of publishing. A lot of those jobs involve holding people's hands, "emotional labor", like nursing and teaching. These jobs are seen as something people (women, mostly) should do because they like being carers, rather than for the money. These jobs end up being paid less than they are really worth, especially since they often involve many hours without compensatio…
Nursing and teaching are surprisingly well-compensated fields with lots of job security and relatively straightforward entrance requirements. It's also true that both fields are valorized, but plumbing isn't and has the same dynamics. These arguments are all overdetermined.
Nursing is also a hard job where the paycheck is nowhere near what doctors can earn.