It is so toxic to work with people who are this entitled. Getting this upset over a mandatory meeting? What a nightmare. You know this is just the tip of the iceberg for their bad behavior if they are the type to publish a seething screed over something so banal.
I don't like four hour meetings either. But give me a break. Running companies is hard, keeping teams aligned is hard. Sometimes keeping things going requires doing things that we don't like. That's just called being an adult.