Don't take my advice very seriously, because I'm 100% impervious to taboos and I don't give a fuck about dead kids, explicit sex, gore, cussing, etc... When it comes to storytelling and art, I'd just do whatever makes the most sense and fits the tone and message of my work better. I can't really tell you "go ahead and do it" because a LOT of people will probably refuse to read/follow/subscribe to your work if it contains any ammount of these elements. It will attract other readers as well, but they'll be little and scarced (a niche audience).
I mean, since it's very difficult to please everyone and write a story that's made for all kinds of people, just stick to a target and write for that target. If you want a lot of subs and viewers, do something that even children could read. Full Disney style.
Well, I understand your point, but if every single character that dies in that story dies horribly, in a very gory and explicit way, then treating the children differently is betraying the spirit and the tone of said work for the sake of avoiding criticism. I worked for a short animated school film in college that had a psychopath little princess dancing around corpses and beheading a guy at the end, cussing included, where several of those corpses were also children (shot, hanged, impaled, you name it). And everyone loved it, the faculty included, precisely because its sheer lack of filter (it was a comedy, btw).
However, I do agree that killing children in a story where that's not normal and in a way that it doesn't fit its tone, only to shock audiences, should be avoided at all costs for several obvious reasons.