Hmmm... that presupposes that no dinner ladies can possibly act in an inappropriate manner. I have unfortunately heard both teachers and one headteacher say extremely inappropriate things- the sort of thing that I probably would not have believed on my child's word alone- so I don't know why I should think there could not be a dinner lady who did the same, particularly as they receive much less training than teachers do.
I have heard a headteacher say reproachfully of a child with serious chronic health problems: "yes, we understand that X is ill but you can't expect us to be happy about it". I wouldn't have believed this if somebody else had told me about it, but unfortunately I was there.
I have every respect for the teaching profession (not least because I am a member of it ). I just do not believe that there is any profession that so perfect that no member of it can ever say anything wrong. And as I said, dinner ladies receive relatively little training and do not necessarily know much about motor development in young children.
This is not teacher-bashing (or dinner lady bashing)any more than complaining about the manner of a HV or doctor is bashing of the medical profession as such.
I don't even necessarily think the OP should take it further, at least not the first time.
But I don't think there is any profession that is so exalted that all its members have to be above criticism.