I'm sorry you feel this way but I don't feel it's something that I should change. For one it was there for long before I was running this thread. In not just the solo challenge, but nearly all challenges on Pokecommunity, when played in any region the challenge ends when you beat the champion. Since Ghetsis is not the champion of the Unova region then it doesn't count as a victory. The only exception that I've commonly seen is for the Johto regions where you must beat Red to complete the challenge, and in some cases you have to beat Steven in Emerald. It's not the point to beat the Elite Four twice, the point is to beat the champion of the region. Again I'm sorry you feel this way but it's not something I'm going to change.