I think one of the major issues here is that we've inherited a post-11 education system that isn't really fit for purpose, regardless of whether a child goes to a comp, a grammar or a public school.
I'm a former secondary school teacher and a former primary governor, and I strongly believe that children that succeed in our current system do so against the odds.
I've never understood why we school 11 year olds in the same institutions as 16 year olds, for example. Likewise, I've never understood why some state schools have been allowed to become so large.
It's features in the secondary system like these that, I believe, lead to entirely predictable problems that then, inevitably, result in militaristic solutions...because you have created the need to control an "army" in the first place, iyswim.
The true solution is not to create such an environment structure in the first place, but that, of course, would require money and a bit of thinking, and I suspect there are just too many vested interests in the status quo.