Earlier quoted context omitted.
It's not surprising: The GPL mostly torpedoes commercial uses, and EA does not want to give their competitors code they can use in their own proprietary games.
There is nothing in the GPL that prohibits you from selling games: https://www.gnu.org/licenses/gpl-faq.html#DoesTheGPLAllowMon...
The vast majority of game studios aren't willing to do this, so effectively releasing it under the GPL means that it's much less likely that a competitor uses the code.
Asset flips from other countries with more permissive (or just hard to access for foreigners) legal systems are already a problem for game developers--releasing the source code for your game would ensure that you'd be inundated with assets flips almost immediately if your game is any good.