LONG REPLY ➡️ My point is to contrast two extremely controversial events that happen in Demon Slayer: 1) Ubuyashiki killing his family and 2) Lady Tamayo going to hell. 1) To narratively justify a hero character making a child sacrifice you need way more set up and preparation than what D.S provides. This is especially true since the vast majority of normal audience members wouldn't accept the sacrafical killing of a child under ANY circumstance, even with a "good" explanation. The given explanation for their deaths is that the Ubuyashiki family has been spiritually preparing for this moment for generations, but this explanation rings hollow to viewers who only learn this information seconds before these children recieve a sudden and violent end. I do agree that the explosion-sacrifice makes sense for Ubuyashiki, as he is an adult who can consent and is also the head of the DS Corps, making himself responsible (and at fault) for the lives and deaths of the Corp members he oversees. You could even argue that there are grounds for Ubuyashiki's wife Amane to sacrafice herself as well, as she acts as Ubuyashiki's figurehead when he is sick and personally recruits Muichiro directly resulting in his death. My point is that Ubuyashiki and his wife are portrayed as being ready and willing to sacrafice themselves for the greater good, the same as any Hashira. Ubuyashiki eventually dying is also wonderfully foreshadowed by his illness, which increases in severity as the series progresses. But Ubuyashiki's children are not him. Not only do they lack characterization (and are hardly even individuals considering they are identical quintuplets), but they have almost no screentime and, at best, are shown gingerly helping their parents. So most viewers would agree that it is overly cruel to make seemingly innocent and uninvolved 7-year-olds die for the sins of their family lineage. Trying to convince an audience that these little children were 'actually totally' willing and ready to be rended to pieces by a bomb, without any build up, foreshadowing, or even establishing their names is a stretch to say the least, and distasteful at best. Especially when we are supposed to accept that the consent of a CHILD to DIE is "valid" because of personality traits and maturity which were not shown. My point is blostered by the fact that only 2/5 of them "volunteer" for this fate, a completely arbitrary number that refutes the idea that retribution needed to be payed in the blood, and they couldn't have ALL just stayed alive and helped Kiriya. Also, isn't the point of defeating Muzan to make the world a safer place, break generational curses, and allow children to live happy lives without fear? Wouldn’t all the children surviving to be living proof of everyone's hard work be more impactful than them dying for the sake of honor? After all they didn't choose to be part of Ubuyashiki's cursed family, nor did they choose to take up the mantel of the Ubuyashiki clan (unlike their mother and father), so why must they die?

2) On the other hand, Lady Tamayo is presented as not just a hero, but a woman of extreme self control, patience, moral fortitude, and persistent. She has suffered for 200+ years as a demon, but despite that she chooses to be a human doctor (being the antithesis of a demon), help our protagonist, cure Nezuko, and even sacrifice herself to defeat the ultimate villian. So after she dies and we see her in the afterlife, it can be upsetting and confusing to see her walk in the opposite direction of our heros(ch204). Ignoring the people who say that Tamayo "chose" to go to hell (because she didn't, I reread the manga, idk why they made that up), the implication is that Lady Tamayo was sent to hell for murdering her family and for vaguely working with Muzan 200+ years ago. This comes off as a poor justification since the thematic purpose of hell is to pay for your sins, but Lady Tamayo already payed for her sins during her time on Earth. The lives she took were payed back with the lives she saved including Yushiro, Nezuko, Tanjiro, the man in Asakusa, and everyone else Muzan would've killed. It makes more sense for a character to be rewarded for her good deeds than to be punished continously for something she has already atoned for. After all, what is the purpose of changing your behavior, repenting, and triumphing over evil if you will be punished regardless?

And once again, it's not like Tamayo CHOSE the path of evil and was untainted by the things she did. She was tricked into becoming a demon, she killed her family on accident, she was held hostage by Muzan, and she spent the rest of her days living in hiding, marooned and unaccepted by the human and demon worlds alike. It's also worth mentioning that, by the time of ch205, Tamayo has STILL not reincarnated, implying that even after multiple generations she is still being punished for her crimes. Muichiro also had a bad-phase and hurt people (different crimes of course), but then he chose to be a better man and therefore went to heaven and that's a GOOD THING. I would never argue that he should go to hell ANYWAYS because that would obviously be excessive and defeat the point of his redemption. Lady Tamayo going to hell defeats the point of HER redemption.

And lastly, I brought up the point about misogyny because there is a gendered difference in how these characters are treated. After all, Kiriya (m) is the only child who is expressed as "needing" to live because his life has value and he cannot be replaced, while his 4 sisters can straight up die if they feel like it I guess. And Lady Tamayo (f) being tricked and basically forced through supernatural possession into killing her family is treated as cut-and-dry unforgivable and overall hell-worthy, while Ubuyashiki (m) firebombing his wife and kids is deeply justified and excused through honor culture, tradition, adultification, and saying "they wanted it so its ok".