Because of beer.
If you are playing a game with four or five buddies, drinking beer is just sensible.
But if you are alone in your basement, playing a computer game wearing only your underwears and cheetos stains... drinking beer is a cry for help.
Now, we all know that life needs beer so you need to drink. But you have to drink responsibly. So drink with friends who are in the same room as you, who aren't imaginary or named 'Badasskiller95'. Drink while playing good ol' tabletop D&D.
What if you've had a beer with your friends at the same table, then flown 1000 km back home to play games with them? Where does that fall? I think the majority of my guild has done that... once you've been there, is it okay to cut out some of the travel and just have a few beers while you all game together connected by voice and virtual presence alone?
Not to single you out, there were a few other posts to the same effect, but I can't help but feel like comments to the effect of 'cheeto stains' are a little
pot-and-kettle. Not in the sense that I think you're projecting (although I do get that impression sometimes from these sorts of discussions), just that if you're going to go on the saddest stereotypes of your target, do the same out of fairness for your own group - and as D&D fans, that's not flattering territory for us, so let's maybe just stay away from there.
If you want to talk realities, our guild of maybe 60-70 active players (approximating here) has seen at least 6 members get married* in the last year or two (those are the ones I remember off the top of my head), just to throw a counter-intuitive little factoid out there. Hardly alone in the basement, and one hardly needs to be to have a few beers and do a few battlegrounds. In fact, I can think of several more who've been married for longer, a couple of which have kids. The demographic breakdown probably looks pretty similar to here, actually, once you correct for the age skew that comes with a ~10 year old forum for a ~36 year old hobby compared to a 6 year old computer game. Maybe you can still sell your point without resorting to such methods, I don't know. I'm kind of replying to both your specific post and the general sentiment of a few others at the same time here.
Closing thought: I guess in my mind, the tabletop vs. long-distance/computer gaming thing is being set up in this thread as a false dichotomy along the lines of roleplaying vs. min/maxing. Why do we do this?
*not to each other!