>>283668431
Putting it that way, Aura wasn't shocked because Frieren did something she found amoral or truly dishonorable, she was angry that her enemy managed to get her with an absurd (from her point of view) trick and baffled that somebody might have come up with such an illogical (from her limited point of view) technique. It's not a moral outrage at some broken code of honour, it's an animal raging at being caught in a trap that goes against its instincts, just with enough smarts to articulate its frustration.
>>283668481
Because Frieren can not only change, but also change without the ever present risk of going berserk and blasting Stark to pieces to check out if she cares about humans yet.
The point is that the demons lack the capability to grow beyond their worst instincts, on level that fundamentally makes it impossible for them to co-exist with them. They also aren't really all that morally capable. In fact, their inability to develop beyond basic transactional egoism is one of their worst traits. They are essentially perpetual stuck in pre-conventional stage at best. Also, their social system is literally limited to a pecking order where stronger specimens order weaker ones and is maintained partially because they do lack the faculties needed to have a few weaker members gang up on the stronger one.
Again, Macht was an exceptional specimen, arguably the least inherently destructive demon we've met so far, and even he has ultimately gone on the rampage simply because he decided it's time to kill everybody who considers him a friend to check if he would care about that and feel sad. Author's notes explicitly stated that at this rate, he would physically run out of humans to kill in his experiments before developing the emotions he wanted.
>>283668564
Because, to no surprise, speech is useful and copying speech is what jumpstarted their mental development of sapience in the first place. That's explicitly the explicitly stated premise.
