Quite a few people acknowledge mental illness as a concept but the reality is they don't believe it's long lasting. It's like that thing that you had that one time when you were low..but you have friends and a job etc so now you must be totally fine 🙄 Only yesterday I read a comment from someone saying that another person's PTSD couldn't be "that bad" if they could hold down a full time job. So discrimination and ignorance come from both sides of the issue - those who have no experience of mental illness and those who have it.
I have dx of complex ptsd, which I'm open about. People still think it's something I have a choice over. That I'm "choosing" to dwell on traumatic events and "there's people who have been through worse". Very recently I fell out with a friend because they give me no room to have memory loss and cognitive dysfunctions even though my full diagnosis (which they know and understand through their job) shows that I am impaired that way.
So this topic is completely relevant. And in broader sense there are many people who confuse depression with sadness, believe bipolar is simply mood swings, believe ptsd is just for soldiers etc etc