A normal person wants to do the best for their children. If they feel private education is the way to go, and can afford the fees then I say good luck to them. Promoting ideology ahead of education is the hallmark of narrow minded, sad bigotry.
The discussion of what is the best system of public education is another matter entirely. Up to the late 60's Grammar schools gave a good education and promoted social mobility. Again the merits or de-merits of the 11+ exam is another issue. The wholesale migration of secondary public education to comprehensive schools has not, in my view, succeeded as well as has been suggested.
I see some here would like to make political capital out of the present education system on offer. Far more important to educate the kids in my opinion.