All you can do is have a moan and make statements that have no evidence to back them.
Misdirected energy. Everyone else should agitate for increased funding for state schools. The current £5k per head is paltry in 2024. Private school parents pay £20-30k (more if boarding) per child on top of paying their taxes and will pay more with VAT. 93% (93!!) of the entire student population use state schools and it seems most of the current government and parliament. It does not get more influential than that! Use that influence and collective action (which is more than the 7% have) to focus on solutions to improve state schools.
I remember a time in the mid-2010s when state primary experience were so good in London that our wealthy friends living in good areas felt no need to send their kids to state schools. Post-COVID, that all seems to have come undone.
Private school parents are not coming to save you - even if they were in state schools, they may simply utilise their resources to support their own children outside of school, or congregate in small enclaves that would make the local primary school feel private in all but name.
It is up to you (the collective you!) to agitate for change in state schools and we have a government that appears to be on the same page. So do that instead of wasting energy trying (and failing) to destroy private schools