the comment I replied to just said broadly "letting one sibling babysit will traumatize that child and they will hate their parents"
It's funny, i thought the exact opposite; your comment was saying that kids babysitting kids will never cause resentment, and the comment you replied to was obviously saying that kids baysitting kids is a bad habit to get into, but not terrible in moderation.
I am well aware that my family situation is an outlier, i just understood your comment to mean that kids babysitting kids will never cause resentment, so one counter example was enough to make my point, which was that you need to be careful about choosing to have enough kids so they can 'parent themselves'.