I suspect the OP might have read something that wasn't intended for anyone else's eyes.
I also suspect that the teacher was being candid and honest without having to put on the 'professional' head you need when talking to parents and sometimes end up talking all around the houses and using 40 words when 1 would do because the 1 might be offensive.
I don't believe a teacher would write "waste of space" in a report because even if one teacher was unprofessional enough to use that sort of language about a parent (although I've never heard anything like that), they would have to be a complete idiot to commit it to paper and if they did, would be hauled over hot coals for it. No headteacher would tolerate this. I can't imagine a colleague would turn a blind eye either.
Unsympathetic and unsupportive - yes, I can imagine those being written to describe a parents conduct/attitude/engagement with the school.
Waste of space - never in a month of sundays. That sounds more like the OP is angry and trying to gain more support by inferring that is what the teacher was inferring.
More than that, the only time I have ever been required to commit any of my opinions about a parent to paper was for the purposes of CAFs or CP conferences. Schools don't keep files on parents!
You could report to the Head, but I suspect the Head has already read the report. If indeed it exists