An interesting admission came in an article discussing this issue:

How the Israel-Hamas war is dividing Hollywood (LA Times 10/24/2023)

On Tuesday, the guild’s [Writers Guild of America] leadership sent an email to its 11,500 members, apologizing for the “tremendous pain” it had caused by not issuing a public statement on the conflict, explaining, “It can be an imprecise science for a labor union to pick and choose where it weighs in on both domestic and world affairs.”

Why is a labor union weighing in on domestic and world affairs? Does the war have something to do with scriptwriting that I don't know about? Doesn't it exist solely for the purposes of protecting the rights of the members and advancing their interests?

Of course not! It's for control, like every other "labor union".