Language makes an enormous difference. Who would you rather have working on your taxes: a crip or someone who is physically disabled? Who would you rather have diagnosing your illness: a girl or a little woman or a woman? Who would you rather trust teaching your kid: a lunatic or someone with a brain chemistry disorder? Who would you find it easier to make fun of: a retard or someone who was mentally impaired?
So-called “PC” terms change the way you think whether you are aware of it or not. They make you take the person more seriously and respectfully. Sure, it’s easy to make fun of the kinds of contortions linguists go through in order to make a more value-neutral version of a pejorative term. Some of them do seem ridiculous. But they work. They help these minorities earn greater respect.
What are you? A sociopath? Or someone who is merely insensitive to the problems of those less fortunate than yourself?