Your whole first paragraph is actually offering another example of a dehumanizing term. The point of “human who does a thing” is to be a naturally-chosen phrase, not a term. Think, “Joe programs computers”, not, “Joe is a computer programmer”. You are correct that it would similarly be dehumanizing if it simply became another term to replace “computer programmer” like “Joe is a human-who-programs-computers” but that is because the statement is about what Joe supposedly “is” rather than being a description of things they’ve done.