Replacing the word "man" with the word "male." It's a very subtle way of dehumanizing people. The generic word "male" can be used for any species in the animal kingdom, but only "man" can refer to an adult human. "Man" also carries symbolic power in it. "I am a man" is more empowering than "I am a male."

This is part of a larger trend of using language to reduce humans to livestock. Young humans are "children," not "kids." Kids are baby goats. "Herd immunity" is another one. A group of humans is not a herd.