Because they are corrupting medical terminology in the quest for idiotic political correctness.
But what harm does it do ?
Any time you choose to alter medical, and scientific terms, for the "feelings" of someone, it is a problem. We have spent CENTURIES defining words, and their application to the various parts of the human anatomy. Ultimately, if this insanity is allowed to continue, the language will fail, and people will die because one person said one thing, but the recipient hears something else.