Abstractions are not per-se "completely neutral". Nor is slavery racist per-se. Historically, it predates the Atlantic (sub-saharan) era slave trade by milleni

Abstractions are not per-se "completely neutral". Nor is slavery racist per-se. Historically, it predates the Atlantic (sub-saharan) era slave trade by millenia. As for technology, its quite common in the field of Hydraulics. That's probably where (electrical) egineers picked up the term. See, eg: https://en.wikipedia.org/wiki/Master_cylinder https://en.wikipedia.org/wiki/Master_cylinder