1 HP does not need 3 units of resource. They need half a unit of resource. Anyone who has ever been a gifted child or worked with a gifted child knows this. Like, I've never given my kid more than a half hour of instruction in a day. I don't push her very hard. But simply putting her in school for the past six weeks has completely hamstrung her. She's too tired to want to do anything after being there for seven hours a day. She was making vastly more progress with what I could do with her during my lunch break, which is how she ended up years ahead.
I literally just want them to group with by ability and move at the pace of even the slowest HP. I was told there were literally at least 15 children who scored 99th percentile national on their first standardized test, and mine only scored 97th, so there's no chance that they'll be able to do anything for her. There are 5 classrooms, so quintiles seems reasonable enough, but like I said, I would actually be perfectly happy with e.g. 25-30 kids in my kid's class while the slower classes get 15. It is entirely about segregation. Her teacher told me that she has to devote her time to working with the kids who can't count to 4, and my daughter has told me at least one kid isn't fully potty trained and regularly wets themselves. I'm teaching my kid multiplication at home where I end up having to do all of her education myself anyway. She literally gets precisely 0% of what she needs, in the same way that putting a third grader in a kindergarten classroom gives them no benefit at all. Fortunately, I already anticipated that being the case, but it still annoys me that the only reason we're sending her to school is to meet other kids, and they're not putting her with the right group of kids, so even the social value is somewhat limited (she has, on her own, happened to latch onto the four smart kids in her class for recess/lunch. Go figure).
The average home in my area costs $1.5 million and somehow this is the state of public schools. As you might imagine, this sort of situation turns you into a NIMBY or pro-vouchers real fast. There's no resource problem; it's entirely intentional mismanagement.
But you were saying "there are too many high performing kids in my daughter's cohort and they don't have enough resources for her to get any support". If HP needs less resource, then I would think that the more there is HP kids, the more your daughter will get resource.
I'm still not sure of your argument. You are asking to split into two classes: one with 25-30 kids (the "smart" group), which includes your daughter, and one with 15 kids (the "dumb" group). But you choose the threshold so that your daughter makes it into the "smart" group. Would you also be happy if they decide to do one class with 25 kids and one class with 25 kids, and your daughter is in the "dumb" group? And if you had to choose between only two choices: either the status quo or your kid in the "dumb" group, will you prefer the second one for the benefice of kids in the "smart" group? It feels like you are asking to redistribute for the benefit of some kids only (and in particular, yours), even if it has bad consequences on other kids. I would not use the term "discrimination" in this situation, but I think it is a terrible state of mind. You need to understand that you are not special: if the school was applying your idea, other parents whose kids are hurt by this idea will come to them and complain like you've done, and if they accepted to change things for you, they have no reason to not accept to change things for them.
I also hear your explanation about how your kid progressed well when homeschooled and all that. But you seem to jump to the conclusion that the difference is due to failure of the school or the presence of lower performing kids. That does not seem obvious to me, especially when you explain that you were not giving her more than half hour of instruction in a day and that she is years ahead (not that it is bad, but that's probably a better explanation why she is not flourishing at school).
In short, I really don't think it is a good example that shows that people who tend toward NIMBY or pro-vouchers are reasonable people.