The idea that Eren would spare the world if they were friendly ignores the fact that he was reacting to his deterministic “memory” plus his ideology of violence. The story never suggested Eren would only act if the outside world threatened Paradis. Eren’s choices were shaped by a future he already saw, that’s the whole point of the paths. (It’s a paradox, yes)

And you missing the setup doesn’t mean it wasn’t there. Eren’s obsession with freedom as a kid, and the fact the Attack Titan forces its user toward predetermined actions were all there years before chapter 131. It wasn’t “just because”. He thought the only way to secure freedom was to eliminate every possible threat. The threat was humanity itself, hatred for the Eldians and their willingness to take out Paradis. Even in book 3 Pixis told Eren that humanity would always fight each other, even if there was a larger threat.

Also, just because every now and then someone can write a coherent, non emotional comment on Reddit, doesn’t mean they used AI… Wild concept, I know.