So just to recap: Writers are unhappy with how major talent agencies have been repping them. When confronted with this, the agents refused to make any changes, so the writers fired them. Now the agencies are saying the writers cannot do this because, according to them, writers are legally bound to be represented by people who they believe are shafting them.
Even by Hollywood standards, this is Absolutely Insane.
Writers are not indentured servants of talent agencies; they are the people who create the stories we all spend so much time and money watching and obsessing about.