Stopraining. Because the ugly truth is that in an affluent area the kids will in general be better behaved because of their upbringing. The few rotten apples will be in the minority and can be dealt with by the teachers
In poorer areas there will be a disproportionate amount of crime, bad families etc. Your child will have low expectations as their peers will have none themselves. They will spend their time trying to survive rather than study.
It's easy for those who are not in this situation or care to say it's wrong. Yes of course it's wrong but then my priority is to my children. As much as I want to, I can't change the world and make all schools better.
The school my council wanted to send my child to was in special measures. It had it's own full time policeman, the new head was in the papers recently for stamping out smoking in the playground. A child killed himself because of the bullying and oh yes, the school had it's own benefits "shop". I kid you not.
So look at it from my point of view. I have a child at a brilliant primary school, ahead of kids her age. She's been brought up "correctly" (ie. no smoking, drinking/sex). Now the council want her to go to that school.
Your alternative is to lie. Would you? In a heartbeat I would! Luckily I had the resources to move. Other parents may not be so lucky. Is it wrong? yes it is. Would I do it? You bet your arse I would!