Tough love doesn't work here. Logic doesn't penetrate. Worse, I worry you could come across as trivializing addiction, depression and other mental health issues.
When in doubt seek help. That is what we need to encourage. And I know first hand how hard it is to seek help and keep seeking it, but the very act can be its own little bit of healing.
No, I think parent is exactly right. I feel similar to the OP, but I know for sure it's not a depression. And I think I suffer the same problem the parent described. The real world just seems so messy and complicated compared to virtual worlds.
You may call it a mental health issue, but it is neither addiction nor depression; if anything, it's just not being addicted to real world enough.
How do you know it is not depression? This is a very personal topic, but I never thought of myself as depressed until I fell into a hole so deep that I had to search for medical help (and then I still thought about EVERYTHING but depression: High-functional autism, ADHD, whatever ..) - diagnosis and therapy helped me tremendously and looking back there would've been zero chance for me to recognize that I was suffering from depression on my own. It's one of the hallmarks of depression to rationalize it away "don't be such a wuzz ... all is fine, you are lazy, stop doing that", so it's very risky to say "I know for sure it's not a depression" - you are probably the worst judge for that (just to make this clear: It's your life, if you feel all is fine and you just don't want to go out then it is fine, enjoy your life - my comment is only intended as a second perspective on a real serious issue).
Depression has certain criteria, for example things like you don't enjoy anything, you feel tired all the time, you consider that you shouldn't live, and so on. I had a mild depression, and I know this is not it. I am happy, I like to meet people from time to time, etc.
It's not addiction either - I spend my days on the Internet (or in computer games) a lot, but if I had to spend a week without it, it wouldn't be a problem. I don't have to be connected 24x7 either. I also sometimes abandon the game for no reason.
It's really just you don't feel so motivated by the things in the real world compared to virtual possibilities. Let me reiterate, I think parent was spot on when he talked about the "artificial Skinner box of instant rewards", and I don't think there is a psychiatric category describing this.
It's not a mental disorder, just like overeating (and being overweight due to that) isn't (usually) a disorder. But yeah, it may be a mental health issue. It's mentally unhealthy behavior, just like eating too much is unhealthy.
When in doubt seek help. That is what we need to encourage. And I know first hand how hard it is to seek help and keep seeking it, but the very act can be its own little bit of healing.