Did you flat out miss the part where the HP nerf (not nerfs) came in well before you made your "Blizzard deliberately made this boss impossible" conspiracy theory post.
This can be 100% proven by checking the following links:
https://www.twitch.tv/videos/155997408 - Alpha's stream from 3 days ago, clearly and conclusively showing Fallen Avatar as having 7159m HP
https://www.twitch.tv/videos/156548726 - Slootbag's stream from today. Where his guild <Future> made pulls of the boss AFTER Method had killed it. And guess what? 7159m HP
The HP has not been changed in DAYS. There have been no HP nerfs in a long, long time.