If you look into actual research on education (it exists), private schools and charter schools are no better at educating than public schools.* It is just a matter of other pre-existing differences, like socioeconomic status (poverty), etc. As numerous people have pointed out - you want to fix education, you need to fix poverty and inequity. Sure, other things will help, too, like requiring all teachers have masters degrees and paying them like other professionals, as other countries like Finland do.
That said, the article that is the subject of the blog complaint states that it is morally wrong to send your kid to private school. I disagree with that - even people who send their kids to private schools pay taxes that go to support public schools. It is a little more of a shame when parents send their kids to (some) crappy charter schools, which DO take away money from public schools, but sometimes it is because the public school really is bad, or because the kid isn't doing well in the public school and the only other alternative is homeschooling.
That said, the article that is the subject of the blog complaint states that it is morally wrong to send your kid to private school. I disagree with that - even people who send their kids to private schools pay taxes that go to support public schools. It is a little more of a shame when parents send their kids to (some) crappy charter schools, which DO take away money from public schools, but sometimes it is because the public school really is bad, or because the kid isn't doing well in the public school and the only other alternative is homeschooling.
* http://www.edline.com/uploads/pdf/PrivateSchoolsReport.pdf http://content.time.com/time/nation/article/0,8599,1670063,0... http://voices.washingtonpost.com/answer-sheet/are-private-sc... http://www.nea.org/home/18142.htm