It's meant to build cross functional teams of people who can produce predictable amounts of output such that people in Product Management can build roadmaps and concoct release schedules.
Not to mention, once a company has successfully implemented Agile (and its inherent trade-off of dev speed vs. predictable minimums) that company may now replace any person on any team with any other person. Nobody wants to say it but Agile is about hiring low rate contractors instead of expensive FTE resources.
An often overlooked part of Agile is that if you're an experienced dev who's also lazy is that this method provides a lot of cover to hide in. It's about predictable minimums. A clever dev with some talent can work about 4h/day and still outwork some of the less clever cohorts who may work many more hours.
Also, you seem very angry and thats a sign you probably care a great deal about what you're doing at work. Maybe its worth looking for something else to do where things operate more to your liking? Stress really is a killer and few things are as stressful as hating the way your job works every day of your life. Reading your story I think I'd be angry too in your position.
Finally, repeat after me here - "Agile is for MANAGEMENT - Agile is NOT for developers". The Happy Agile Developer is one who's figured out how the game works and uses that understanding to work less.