1 - Anti-meritocratic. No level playing-field. Hinders social mobility.
Typical leftist mentality.
The state can't be better than the private system, so let's drag everyone down
by force to the level of the state.
And they're quite meritocratic - they reward the person who has enough merit to afford them for his children. Even if they weren't, being non-meritocratic and hindering social mobility (though that, again, is grossly incorrect) is not a crime as long as it does not violate anyone's rights.
Nobody has a
right to an education better than they can afford.
2 - By removing many of the best teachers from the state system they hinder the state system.
Ah. So let's
force teachers into a system where they're unhappy, and forcefully destroy a system where they're happy. I wonder what is more distasteful - the state having to compete in the market as an equal, or your forcing teachers into a system which they may not like.
3 - By removing many of the more privilidged students they hinder the state system.
So now the privileged are not entitled to the right to free association?
4 - The social devide they create perpetuates a seperation of the haves and the have nots - to the detrement of both groups.
Again, unequal opportunity is not a crime or something. As long as a basic minimum is provided by either the state system or by societal institutions, nothing more need be given.
By having private schools, it is not the rights of the students that are being protected, but the right to parents to do as they will with their money, their (and their childrens') right to free association, and to the pursuit of happiness. By banning them, you violate all these rights.