mama - parents need to take their share of the responsibility. When I was at school, I was more worried about what my parents would say if I got into trouble than I was about any of the teachers. My parents supported the school 100% and were sensible enough to realise that I (or my sister) would very likely present a somewhat editted version of events if it came to that. These days, many parents (like you) don't support schools, leading kids to believe that they can behave any way they want.
And you knnow what, forgetting equipment, if it's somthing which happens again and again, isn't "stupid" - it gets in the way. No PE kit, no pen, no homework, no French book - kids need to learn to be organised. I don't imagine many adults would get away with constantly forgetting case notes for a meeting, or the prepared handouts for a presentation at work without getting pulled up on it.
Fighting parents' unsupportive attitudes is not something teachers should have to deal with. Education is not just something a teacher and a school has to provide and child has to take. It needs to be a three-way partnership for it to work effectively. Your "no child of mine is ever going to do an after school detention" attitude stinks.