Where is the center? In the middle, right? So how can the center be around something? Aren’t these two concepts a bit of an oxymoron when placed next to each other? You’re either at the center or you’re around. Will everyone please stop saying and writing “centered around” now?
If you really feel the word “around” calling to you, try out “revolve around” instead. Maybe it will make you feel better.
“Centered on” is the proper phrase here. (At least in American English. Oddly, in other parts of the world “centre on” and “centre around” have become largely interchangeable—though “centre on” is still regarded as the proper form of the phrase. But note the spelling change of “centre” in these cases. Unless you’re spelling it like the Brits, stick to “center on.”)
It’s rare the Americans are the stricter grammarians, isn’t it?