"I Can't Afford to Sue DC": Fables Creator Releases Hit Comic Series into Public Domain (Including Wolf Among Us) (screenrant.com) Summarizing his statement wouldn't do it justice so I recommend you read it in full, he explains why he does it and what has DC done to anger him to this extent - but it's also a move about more than just to spite DC....
"I Can't Afford to Sue DC": Fables Creator Releases Hit Comic Series into Public Domain (Including Wolf Among Us) (screenrant.com)
Summarizing his statement wouldn't do it justice so I recommend you read it in full, he explains why he does it and what has DC done to anger him to this extent - but it's also a move about more than just to spite DC....