Gosh, some of the language being used on here to refer to non-grammar-school kids is appalling. 'Scrotes' - really?
I get that some people may have had a horrible time as a bright kid in a comp - I'm guessing 20 years ago? But children who don't pass a test on a single day at 10 (especially considering the fierce amount of tutoring that goes on today) don't deserve this kind of blanket dismissal as feral dimwits. I honestly can't believe this needs saying.
I get that people may have had a horrid time at school and I honestly do feel for you - it's shit that this happened during such formative years. But extrapolating from your experience to venting this kind of vitriol towards the vast sweep of ordinary kids today is frankly out of order.
As a counterpoint to your experience, I was a child from an extremely poor background (that's me, not my parents). My family were what would be described by certain news channels as the 'underclass' - not working, on benefits. I had free schools meals right the way through school, was undernourished, one bath a week, yadda yadda. My mother didn't put me in for the 11+ - it wasn't even on her radar. Off I went to the (non-leafy) comp, hearing the snide comments from the grammar school girls on the bus about the 'stupid kids'. Maybe they now refer to the children at the local comp as 'scrotes'. I got straight A*s at GCSE, higher than any girl at the local grammar school that year. Straight As at A level, then on to Oxbridge. I was in mixed classes for a fair few subjects. Yes, there was occasional disruption, but the teachers were adept at differentiating work and I got my head down. It was fine.
And I wasn't some sort of major exception - there were plenty of academically bright children in my year, along with others who were lovely and kind, but not so good at exams. Often the latter were highly talented in another arena or had outstanding people skills. The majority of them have grown up to be decent, hard-working adults. There are plenty of bright, engaged and decent kids in comps and secondary moderns up and down the country. You cannot dismiss children in this blanket way.