Yes, I caught this too. According to the definition:
The definition can be found here: http://www.who.int/features/qa/gaming-disorder/en/
This tells me they class it along the lines of gambling addictions. I guess by the WHO classifying it as a disorder, now folks who suffer from it can get the support they need. Of course, that is where THEY classify it - I think all of us can come up with examples of where small-time addictions are evident. I too have struggled with what I consider to be gaming addiction growing up; only after changing priorities and finding the balance in my life did I manage to avoid the worst of it. However, I found that I still find joy in gaming, so I plan when to take some time to game and plan when to turn it off - easier for some than others.
I think that like most of our vices, the secret is moderation. Please everyone - enjoy gaming responsibly.