My impression is that it is used to discharged the "humans should be in a similar situation" semantics of "equality", a meaning that threatens the hierarchies and very unequal distribution of goods in our society, and replace it with "everyone should be treated according to the same rules", a much less potent idea, that was already adopted by the liberal democracies of the mid 19th century, and that doesn't prevent gross inequalities - in fact it is perfectly compatible with, say, modern finance.

Equity means your dollar has as much say as other people's dollars in how a company is run...

Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.