The question is good, but the answers provided by Zoë Pollock on The Dish aren’t all that informative. First, they seem to equate meditation with Buddhism, which is less than half the story. Second, they don’t really talk so much about meditation as about Buddhist philosophy. And, disappointingly for an otherwise interesting blog, it doesn’t even do that very well.
While you’re meditating, you are of course (in most cases) closing your eyes to what’s going on around you. Without invoking Buddhist or other philosophy, I can think of the following reasons why doing so is not selfish, but rather the opposite: 1) it gives you more energy to care about the world around you; 2) it helps working through some of your less mature and more selfish psychological traits; 3) it widens your perspective, making you see yourself within a larger totality; 4) it helps you relinquish some of your excessive identification with your own narrow self. I guess one could find other points.
This doesn’t preclude cases of people using meditation for selfish reasons, whether it’s because they get hooked on specific “states” (blisslike or otherwise), or because they use their renewed contact inwards to argue for solutions that “feel” good rather than ones that do good. I don’t know if this can be blamed on meditation, though. Anybody can make anything into a tool of their own egocentricity. Basically, I think meditation works against selfishness.