wanted to know why so many games jams hate AI usage
It is not hate. Jams are about restrictions. You need to conform to the topic of the jam. That is an restriction.
Using an AI where you just could enter the restrictions as a prompt kinda defeats the purpose. And many jams do allow some ai usage.
Go to ai jams and make games for those. There are ai jams. But with the craft of game making, using ai a lot makes it a new craft: ai prompt crafting. You would not compete in an oil painting contest with photography either. You would compete in a photography contest.