Well, I think part of the criticism of the blog post is that it's written as if the person must actually have had clinical PTSD. Otherwise he wouldn't have any cause to get preachy about how terrible it is to joke about it and "knuckle through."

It's terrifying that you don't understand the difference between stress and traumatic events. That you don't understand that it's not cute to compare yourself to people who have debilitating flashbacks.

The difference between "clinical PTSD" and your "PTSD" is one is actually PTSD and the other is you need some help destressing. If you even had half an insight into how bad PTSD actually is, you would trivalise it. With nonsense claims such as "I got PTSD from being stressed".

Secondly focussing on whether or not someone has been diagnosed is kind of missing the point.