Saying males or females is putting emotional distance between you and the subject. One possible reason for creating that distance might be to dehumanise, but it

Saying males or females is putting emotional distance between you and the subject. One possible reason for creating that distance might be to dehumanise, but it's far from the only reason, as you presumably know quite well. If you or anyone else didn't know, consider a police report or a research paper in which the language is deliberately distant to avoid biasing the reader: "The two female victims were struck by the SUV, and the male suspect fled on foot", "we observed higher rates of CVD for males in the treatment group, but in females the effect size was not significant", and equally bloodless language. This may be dehumanising in some sense, but it's done in a benign way to help the reader be objective. It's easy for a non-native speaker to make a mistake in informal language after reading formal material like the aforementioned, and it might not be great to call out minor breaches of etiquette in such a targeted and public way.