>>719138457 (OP)
It worked on release because it maintained a mystique behind the reapers. They're greater beings than us, thinking on higher levels... cosmic horror. Revealing an unbelievably stupid motive for their actions made it retroactively fall apart.
>we're a big bad AI harvesting organics by killing them to save them from inevitably creating big bad AI that will kill them anyways. ;)
However, I vaguely recall the original idea behind closed doors was that the Reapers were desperately trying to solve entropy. That would have made the line make sense even well after the reveal. Entropy is real, it's ever encroaching. But it's also such a far off problem. To a race like the Reapers that experience their time in great lengths, basically immortal and destined to see entropy to its natural conclusion, they have a reason to fight it. But the short lived races, they'll never see it. It's trillions of years away, every human, turian, asari, etc. alive today will be long, long, long dead by the time entropy becomes an existential issue. Which means they'll consume, contribute, potentially even accelerate entropy without even considering the consequences. If you really think otherwise, consider how the galaxy treats every other long term problem. Consider how we treat long term problems in the real world. It doesn't have to be a buzzword you dislike, it can be anything you see as a genuine issue that goes ignored because the effects aren't right in your face screaming at you to be addressed right now.
And in that sense, Sovereign was 100% correct. We're stupid creatures incapable of the foresight required to think and act on their level. We have done literally nothing to show him otherwise, even. Hell, just look at how the council pushes the Reaper threat to the back burner in ME2 just because it's not in their face anymore.