looks like there are few reasons for the outrage

1. they deleted daily challenges which were reworked like a year ago and replaced it with this worse implementation (these gave lots of xp, not anymore)
2. this is the main content update for the month?
3. they promised to listen for feedback, but in true jagex fashion they ignore all mtx related feedback
4. battle pass comes with buffs for some content which may spiral out of control as time goes on
5. the game has sub fee, loot boxes, store and a battle pass which is fuckton of monetisation for less content updates than 10 years ago
6. battle pass is LONG grind to get everything, and its probably limited time only