If you look at the OP's posts on this thread it looks like she may have routinely used "Reply" rather than "Quote" when responding to people. However, she hasn't @-mentioned the person she is responding to, which makes her replies very confusing: https://www.mumsnet.com/talk/education/4908580-headteacher-used-a-biscuit-in-maths-and-tried-to-feed-our-coeliac-daughter-and-when-told-not-to-laughed-about-it.
I'm guessing she is an inexperienced mumsnetter, but she's not the only one. What is the point of the "Reply" button if it isn't obvious who the reply is aimed at? Surely the person being responded to should be automatically tagged so that it's clear?