Responses
Cause they are confused or have more high expectations meaning they want eren to destroy the world (The yeagerist maybe ┑(￣Д ￣)┍). Little did they know the history will repeat and eren will not reach his end goal if that happens. Basically, a time loop ending and I think its more worst because we will just see eren failed badly.
Also, the part that everyone calling him a chad, mastermind, etc. He is putting up a facade/fake.
I personally love the ending it perfectly fits the story but it was rushed. I'm confident will have more in the anime. ლ(´ڡ`ლ)
Wth why are ppl dissapointed at the ending? what ending did you guys want? For me the ending was pretty good ┑(￣Д ￣)┍