Courts operating with a constitutional mandate are just about the only way to vindicate the rights of the minority as against the majority, and that’s what’s happening in this case: Conn. has a constitutional provision that requires the state to provide adequate education to all children. That is about as close as we’ll get to a law that stipulates equal funding. And that’s really the crux of the court’s decision: the state (not any political subdivision) has a duty to provide adequate education to all; the towns are a terrible mechanism for doing that.
You’re absolutely right that a change would be politically unpopular because it’s not beneficial to a majority. All I can say to that is that the happy majority is cordially invited make honest arguments about why their children deserve more than other children. I know everyone believes their kids should have everything, and everyone else’s kids be damned, but we’re talking about policy here.