They do this because the majority of FUT players online I think used to get coins by playing the ai at world class and mostly winning. EA in their typical fashion didn't want this because they prefer it if you get frustrated and spend real money to buy coins and buy packs.
So the world class ai is now just hilarious in how it cheats, even though the talented dev team claim they just improved the ai decision making.
When the devs make the ai blatantly break the rules of its own game, and do things the player cannot, when the devs handicap your defenders so they run out of position and run away from the danger areas, and make them run like they are in quicksand, while the ai is zipping around... The devs present themselves as a group of clowns.