I do believe in a meritocracy. Private school is the opposite of that. People chances are determined by their parents' ability to pay.
You may not class your children's education as a luxury in terms of facilities or buildings. You may be just in it for the smaller class sizes.
But do you know what luxury those smaller classes also have? No poor kids. Apart from the 1% who are on 100% means tested benefits. Even the ones who you don't consider 'wealthy' have enough spare cash to pay the rest of the fees, and enough priorities, drive and resolve to make it work.
So your kids don't have the educated alongside those who are going to food banks, who are coming to school without breakfast, or in dirty clothes, or who have chaotic and dysfunctional lives. Sure, there may be a bit of dysfunction but not nearly on the same scale.
Your children have the luxury of not knowing those other children exist, or living alongside them, unless they happen to volunteer at a foodbank for their DofE.
That's the bit you don't want to say out loud but it is there for all to see. I don't blame you but don't dress it up as a virtue.
@Another76543 you could make those choices to pay your way out of those dire state schools, other people cannot. That's not your fault, nor should that affect your individual choices.
But the problem is when you don't have to deal with it, or even look at it, it stops becoming a political issue. So people vote according to tax rates, or Brexit, and pretend they don't but know that the terrible policies that have targeted the poorest in society don't affect them, whilst congratulating themselves on the amount of money they save the taxpayer and wanting gratitude. Their complacency costs a lot more.
I find the 'I pay for things I don't need so be grateful' attitude is deeply offensive. It's not how society works. Do you feel that way about the Health Service too?
Society works best if everyone has a vested interest in its systems. You can been sold a lie that you can buy your way out of it.