Maybe taking in stray kos aren't such a good idea. Considering that even though these don't look Deibu/Bawiza/Awize/Badtchouli-ish types, they could be like that once they start taking in to the anon.
Or it could just be that this anon is a total dumbass about yukkuris, since he's had 3 dead already. Either way works, I guess.
I'm pretty sure you could give Anon a badge-quality yukkuri and he'd find some way to kill it.
Probably by feeding it dish soap because hey, the stalk was green and the soap is green and yukkuris are food and food goes on dishes so it'll work amirite?
Okay, just one fact you may want to consider before slamming on this anon.
It is heavily implied that the baby Reimu CANT SPEAK HUMAN, aside from 'take it easy' and 'its like flying in the sky'. Reference post #30529
So, while the harsh 'teaching' the anon is using is responsible for some stress, the fatal amount seems to be coming from the 'kusoyama' name that the anon is using. Since the anon cant understand her, the Reimu builds up stress from what she (may) perceives as constant insulting, while the anon cant understand her complaints in order to know to stop.
Not that this anon should try to raise any more yukkuri. I mean really, after 3 of the babies you try to raise DIE after a day or two, it should be pretty obvious that you're doing it wrong.
I think the name was the straw that broke the camel's back, considering all the other stuff he inadvertently did to terrify it, the name was probably what finished it off.
Also, RIP damaged hat Marisa; your fate will probably be no different.