It's clear what is being discussed here, because "promiscuity" has a simple understandable meaning. In certain contexts the word has a negative connotation, but only because those contexts morally disapprove of the condition the word describes. One would have hoped that "native speakers" could have offered a different, more suitable word to employ in this discussion, rather than just ruling the discussion out of bounds because they don't like this particular word.

Promiscuous is a pejorative term because the act itself is socially seen as negative. There is no way of describing promiscuous behaviour positively, so the choice of word is irrelevant.