There are people out there too lazy to do this themselves, if that ebay guy is actually selling them, good for him. He found customers willing to buy his overpriced merchandise. He is the Apple of Game Case sellers (ironically, I am on my MacBook right now).
If they weren't so overpriced, I wouldn't really care. If he had them for $4 a pop to cover ink, paper, case and time invested, then I think he would be giving a fair deal for the lazy gamers. Like what was posted before, we don't own these covers, they do not contain original art we made, and we can't claim them, so getting sour at the use of the covers here for profit is meaningless as this is a public resource and we cannot protect it without losing the entire reason we exist.
Just keep on keepin on.