In CA, the original reason for charters was to allow small educational experiments to begin and to be replicated in bigger schools and districts if they worked. You see some charters in academy models, some in technical models, some in residential school models. It is supposed to be a one-size fits some organization. The original charter law in CA had nothing to do with building up poor areas or supporting minority education. Some people started charters in these areas because of the ability enter education without a lot of fuss. It was easy to simply do no worse than the local school and still look better. Others had a true commitment to social justice and closing the achievement gap. But this wasn't and isn't the national intention of the charter school movement.
It is also illegal in many states to cherry pick students. A lottery is a lottery- numbers go in, numbers come out. Some charters are allowed lottery preferences where a certain percentage of students get in based on Title I, Free and reduced lunch eligibility etc. But it's still a lottery.
