I don't bash state school kids, or judge them or assume that every single one of them is the same and will get no where in life. Then why is it acceptable for you to do the same?
I'm privately educated but I'm on a bursary and I'm not a 'posho' or stuck up and my friends who do pay for their education are far from being so!
'Clearly this has a profoundly deleterious effect on their ability to succeed in later life, which is why there are so few privately educated people in politics, business, the law, culture, the media, and so on.....' A very very wide generalisation there that you might want to be careful of. Only about 14% of the country's education system is private and in the top universities near 48% are privately educated students, so your claim is unwarranted. It's not right for anyone to discriminate against people whether they paid for their education or not, and it certainly doesn't mean you can start with the reverse discrimination!