Just to be clear, I'm all for treating people with respect, as any decent human being should be. And political correctness is perfectly fine and necessary in most cases, but in most contexts it refers to conforming to certain narratives to avoid scrutiny and being ostracized, which typically only exists to serve some underlying agenda. It's been taken to the extremes lately and conflating "political correctness" with "treating people with respect" is a mistake, because more often than not, political correctness does more harm than good. Imagine there's a serious security flaw in some software but no one will speak up about it because it might result in ostracizing whoever does speak up about it because it offends people. The more freely people are allowed to express themselves, the better off we will all be, regardless of the message. But yes, when speaking freely, one should also be respectful. You can be politically incorrect and treat people with respect at the same time. That is why those phrases are not interchangeable.