I reckon jealousy is a major factor and a lot of ignorance. I actually think deep down if people did have the money alot of parents
would send their children to private school!
I agree with you that a lot of people simply haven't had much to do with people who have gone to schools like Harrow, Eton, Marlborough etc and just perceive they must be out of touch and snobs. A lot of my friends (and OHs) have been to those schools and I have no issue with them and certainly don't think they are snobby (apart from occassional funny comments, such as my OH's ex-flatmate who geniunely couldn't believe that anyone could possibly live without a dishwasher).
However, we can afford private education but are choosing state. I'm simply not convinced that it's worth the money, but I understand your reasons for choosing that path. I do also agree that usually facilities are much better and certain non-academic opportunities, such as sports may be greater.