I don't mind saying "I have depression" or "I am depressed." What bothers me is when the diagnosis is turned into an adjective, such as saying "all the bipolars" or "all the depressives." Person first language is not denying the above or not saying the above. You will notice those statements all say "I". Who starts a sentence "well, as a bipolar..." No one. If someone wants to refer to themselves that way, whatever, I don't care, it's your life. But don't refer to me or all of us or others who have not given consent to be referred to as "autistics" or "bipolars" or "depressives" or "schizos". That is my preference.

I think it's important to note that not all people with disabilities feel the way the person in the article you mentioned feel. I also think a lot of it is about context and sensitivity. And that is what's often lacking when someone misuses the terms and then claims that it's okay.

FYI, I'm not answering this to engage in a debate. I'm just responding to the OP's questions on how I think and feel about it.