I think this pretty much sums up the ridiculousness that is Power Girl.
They actually did use that explanation at the time, and of course she ended up finding out her origins and… boob hole stays. xD I know people who like the boob hole, and I also get that for many, there’s a tradition in the costume, so this isn’t a shot at you if you like it, but that flimsy explanation was just far too eye-rolly. I doubt you could explain it outside that she wants people to see her breasts (or somebody is forcing her to wear that costume), and I’d be okay if they just said that, or admitted as creators what the hole is for, but don’t pretend.