Maybe I shouldn't, but ok, I'll take this on.
Some context: I'm a fairly conservative Christian. Also a teacher. Worked at a public school for eight years. Now work at a private Christian school. Made the switch not for ideological reasons, but because a job came available at the private school teaching AP Literature, which is something I always wanted to do. I also live in a bizarre state as far as education goes, where around 20% of children attend private school because of a host of unusual historical and cultural circumstances. Anyway.
Used to attend and teach Sunday School at a conservative (but very friendly and relatively open-minded) Protestant church for eight years, until I married into a more liberal (but what I would still consider Orthodox) Protestant nondenominational church.
It's safe to say I have pretty wide personal experience with the three broad categories of education: private, public, and homeschooling. I've known a lot of homeschooling families over the years. I actually did a qualitative research project on homeschooling as part of my graduate thesis in education. I've also taught a number of students who came from homeschooling families, because it's not like once you decide to homeschool you have to do it forever.
Theoretically, I'm not really in favor of homeschooling, to be honest. I'm not super vocal about this opinion because I know how deep people's feelings on the subject are. In the end, families have to do what works for them, and I get that. I have two kids of my own, and I know that the gap between theory and practice is often a mile wide.
In theory, I think we should have universally good (not with over-the-top resources or anything, just a reasonable amount--but good luck getting anybody to agree on what that would look like) public schools that separate church and state (without too much fear of either, from either side) and focus on a (mostly) thoughtful, well-rounded curriculum that attempts to build critical thinking skills and a solid foundation for all children's future career hopes, whatever they may be. And I think everyone should have access to that, and the vast majority of people should participate in it, because unless the vast majority participate in it, the whole thing starts falling apart.
Some issues I've noticed with homeschooling over the years:
1. If I'm not using public education, why should I pay for it/care about it/support it/vote for it? But if it's bad, and it's a public resource, and we live in a representative democracy, than ultimately, it's our responsibility to help make it good. Right? When it comes to public services, I don't feel so comfortable treating them the same way I treat Wal-Mart or Starbucks. In other words, I don't see that boycotting a public service is really a great way to affect change. It just seems kind of selfish, and ultimately destined to make things worse. But hey, that's quite a potential political rabbit trail and maybe I haven't thought it through enough.
2. When I talk to homeschooling parents, so often the major justification for their choice is based on fear. And as a rule I've noticed that making major decisions based on fear is frequently a poor strategy. Fear of kids learning paganism. Fear of kids encountering bad influences. Fear of kids being told that God isn't real or that Christianity is stupid or that it's ok to have sex outside of marriage. Fear of secular normative cues leading to a questioning of the values taught by their families.
I understand these fears. I have them myself, honestly. But one of the most frequently repeated phrases in the Bible is "fear not". If I believe that Jesus is true and that my belief system is the only source of true peace, what am I so afraid of? And it's not like private school or even homeschool = perfect environment with no horrible normative cues and no potential issues. There's sin everywhere. Even (oh, especially, let's get real) in my husband and me. Even in the Bible (been rereading Ezekiel this month. Boy howdy, I don't think my kids are allowed to read that one until they're in college).
3. I can almost always spot a homeschooled kid a mile away. Not saying they aren't charming. Just that they stick out like sore thumbs. Maybe that's a good thing. It's often not an easy thing...for them.
4. Some homeschooling families are amazing. They have children who turn into self-assured, accomplished adults. I applaud them, but I always think it's a little sad that those children weren't available to influence the cultural norms of the schools they could have attended. Salt and light of the world. I know those homeschooling families say that as children, it's not an appropriate thing to ask of them to be strong examples, but I'll tell you what, the brave Christian public school kids I've encountered over the years were pretty amazing at influencing their peers in positive ways. Many of the brave secular public school kids have also been amazing positive influences. As a teacher, I can say that it only takes one or two emotionally healthy, strong kids in a classroom to get the whole class going in a good direction. And that's the kind of thing that builds leadership skills in kids.
5. Some homeschooling families are not so amazing. Their children flat out don't get educated. Those families have not been the majority among those I've known--they are outliers just as the exceptional ones are outliers. And I haven't done enough research to know if either group of outliers would have had similar outcomes in conventional school settings. But the nagging knowledge that families take on the education of their kids with very little oversight always gives me pause as a matter of public policy. It doesn't always go very well. That's just a fact.
I don't fault anybody their decision to homeschool, because what you do with your own kids is so personal and so fraught with emotion and unique circumstances and a huge desire to do the right thing. And what I see as the greatest value of homeschooling is not against more conventional schooling, but for the wonderful benefit of getting to spend a lot of meaningful time with your kids, hopefully deepening your relationship with them. That's a big argument in favor of the concept, at least in my book.
I just think it's a bit risky as public policy. The economics of the decision to homeschool will probably permanently render it a fringe choice, as far as I can tell. So I think this is really just an intellectual exercise; one that I like thinking about a lot, since education is my life's work. I can see both sides of the argument, and I'm not really a fanatic one way or the other.