MC looking for his companion, feeling responsible for twins being called evil, having some strong opinions on the goddess and clueless about common knowledge of this world that the native inhabitants are very dramatic about... I'm guessing the "evil twins that hurt the goddess" could be well related to MC, perhaps the companion he's searching for is his twin? They are summoned by the goddess but a conflict occurred then MC+companion hurt goddess to escape etc? or maybe he's a descendant of the twins? Anyone with spoilers can give some hints I'm curious lol
The kids being able to recover so fast from such a trauma deserves high praise tbh, I can't imagine if I could ever recover if I experienced such a horrible life, at least not a big change in personality and outlook on life and trust in humanity.
Side topic, tldr:
Religious, cultural and/or societal influence on humans' perceptions on reality through brainwashing, gaslighting, twisting/nitpicking/cherry-picking the truth to fit narratives, etc aren't really "new practice" or profound in the way that modern society isn't aware of the consequences IRL. In history, during the time when female rights were barely existent, newborn female babies were directly disposed of due to the belief that they weren't a productive labour force, not to mention the infamous witch-hunt, scientists branded as heretics etc. There are still many pointless conflicts, discriminations, fear and paranoia stemmed from those teachings happening to this day. It's just that it's really frustrating and saddening to see because it's mainly caused by the authorities, reinforced by the blind followers and nothing much can be done because most of the time societal formed morality is basically tied to religious teachings in many countries and they can hide behind religions and laws on a "moral high ground" that followers of the same religion would support. Generally, no one can change such a reality, not if people don't want to change for the better, authorities and followers reform and better their religious teachings from within their religion.
Basically, what I'm saying is, most common people want to believe they are good people, by following the religions they have, that (taught/brainwashed/misled/whatever-you-called-it) them the ways, and with faith (which is consistently encouraged to just blindly believe) they feel what they do is justified and moral, regardless of whether they are aware of the consequences of their actions to others, regardless of what their conscience tells, they "believe" they do good. Not saying that their actions and behaviours are justified, excusable, negligible or should be supported, but it's just that in reality we can't really label them as "evil".
Sheep, lack of personal moral compass, gullible, easily influenced, paranoid, selfish, cruel, unkind, have existential insecurity or despair, seeking redemption and willing to sacrifice own values? Could be.
Malevolent, evil, deserve misfortune? Unlikely.
In the end, humans are flawed, humanity is never perfect too in the first place, and so humanity includes the selfishness and cruelty that humans display. To be humans and live in human society is bound to have such humanity issues.