Trying to define what should be meaningful for other people is pretty arrogant and an insular perspective on life. My personal take on reality is that the whole shebang is a "meaningless treadmill", but I'm willing to accept that it might not be true for the next guy.
The easy part to culling the bullshit is to ask yourself: Is this activity making a positive, tangible difference in my life or anyone else’s life?
Easy for him, maybe.
It's fine to make the limited argument that certain games devolve a bit too quickly into flavorless tickling of the brain's pleasure centers. So long as you are clearly arguing about taste in game design, not about the ultimate meaning of life.
But when you decide to delve further, to the point that you've argued not just that crack cocaine and MMORPGs are ultimately meaningless, but also that education, money, casual acquaintances, success, and writing comments on HN are ultimately meaningless, shouldn't you keep going until you get to the end? Which would be something like:
All achievement is porn; that is, it is ultimately empty.
Although I would never phrase it that way; I prefer a more classical phrasing, like this [1]:
Life means suffering.
The origin of suffering is attachment to transient things and the ignorance thereof.
Now that is a general principle.
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[1] I cribbed these lines from http://www.thebigview.com/buddhism/fourtruths.html , because that's what came up in Google. There are probably a few other sources... ;)