I did not care for this article because it seems pretty New Jersey centric and therefore not representative of the whole of charter schools. Minnesota does not allow its charter schools to discriminate on the admissions. In general if you live in Minnesota and are of the appropriate age for your grade level then you pretty much are accepted in the school. If there are more applicants than available spots then it goes to a lottery system. There are few minor exceptions here and there (eg sibling preference) but mostly it's open and fair.
Maybe Minnesota is unique in this regard I don't know but I live in Minnesota and am interested in charter schools as I have school age kids and I just witnessed a new approval for a charter school today (quite by chance on the same day of this