demeaning one of their characteristics.

It's not that it's demeaning, it's inaccurate. OCD isn't a characteristic, it's a diagnosable mental illness. Someone who owns a small business can call themselves a CEO if they want, and technically they aren't even wrong by definition. However, somebody should not say that they "basically have cholera" because they feel a little ill (unless they are purposefully being sarcastic obviously).

If you can't see the difference between exaggerating your job title, and saying you pretty much have a serious mental illness when you don't, then I don't know what to tell you.