Is Christian schooling bad?

I've heard the argument that Christians attending their own little insular school and dealing with their "own kind" is sinful because we are not evangelizing. If the Bible calls us to be salt and light, why don't all Christian children attend public school? They ought to be able to influence their classmates and maybe even their teachers more than they are influenced.
There are few reasons this theory doesn't work. First, during the formative years of a child's education they are not learning as much as absorbing. Before the critical thinking skills have developed (around middle school) all they do is accept what is taught them. If this information is not saturated with a Christian worldview, the child will grow up as a Christian in name only; they will really think in a secular way just like their classmates.
So what about high schoolers, who ought to be able to defend themselves and not accept everything spoken by their teacher? Assume that they attended a Christian school kindergarten through eighth grade - wouldn't it seem time to step into the real world? Yet the pressures to fit in and be cool are stronger in high school than ever. Exhibit A: peer pressure; a hard and fast reality. The dorky kid who protests against evolution will immediately be labeled and set aside as atypical, if not bullied. Exhibit B: teachers whose job is to instruct students. Nothing is worldview neutral - a Realist mathematics teacher will teach Realist mathematics, and force their students to think and do Realist mathematics. Think the Christian might be able to suddenly convince their teacher Realism is untrue and convert to Christianity? Think again. These teachers have had 30 plus years (50 plus for some) to consider their worldview. They decided what they believed long before the Christian student was out of diapers.
In addition, parents must realize that the high school years and extremely influential in shaping a person's life. Students are beginning the transformation from kids to adults; any influences during this period will be especially potent. Do the parents feel their kids can get enough Christianity on Sunday to last them through the rest of the week at government schools? In a culture of cheating on schoolwork, foul language, drugs, and sex, will the Christian hold strong? Sadly too many, at a crossroads in their intellectual life, decide that these things are more attractive than stuffy old religion.
Also consider that if a Christian attends public school, they will usually have secular friends. Like it or not, they will pick up habits, attitudes, and language that their friends use. A proverb I don't know the reference to says: "Bad company corrupts good morals." A high schooler is still developing intellectually, spiritually, physically, and emotionally. They are in no position to handle the barrages of the secular culture 7 hours a day, 5 days a week. "Would you send a baby into battle?" (Mr. K).
Richard
P.S. Please comment - holes, arguments I should have included (this isn't comprehensive =), well dones, etc.