There are many, many reasons a parent would choose to homeschool. While some of the ones suggested in this thread may be true, they are not the only reasons. I do have friends with bullied children that they removed from school. There are lots of special needs kids being homeschooled, as well. In my particular case, I had absolutely no idea that my children were being taught math and reading ONLY until the 6th grade. That "reading" basically covers how many words they can read a minute and comprehension of what they read. No great literary works, poetry, or writing. No spelling. Our local schools ditched spelling. No history, no science. My children, when I removed them from school, were all making straight As and in advanced placement and gifted classes. They scored "above average" on their standardized testing. However, they couldn't name the 7 continents, major bodies of water, or define photosynthesis on even a basic level. They'd never heard of Ponce de Leon or the Fountain of Youth. No idea who sewed the first American flag or what Paul Revere's ride was about. The list goes on and on. I loved my kids school and their teachers, but basically, their hands are tied. This "No Child Left Behind" crap basically makes them teach only what's required for standardized testing (funding.) The school was failing AYP and basically, they can't waste any time teaching what's not to be tested. They also teach how to take the standardized test. That's all they do. My children deserved so much more.
Our school still prays over the intercom and at the beginning of events like awards days and graduations (Shhhh...) so, no, it wasn't to keep them away from non-Christians. And yes....I live in the deep South and there's lots of assumptions made. We also weren't running from any different races from us. Our public school is 95%+ white, just like us. (Redneck, at that. Haha)
I love that my children have not only now learned those continents, but can name the majority of countries on the map. I was able to introduce them to Walt Whitman, Mozart, robotics, world history, foreign language and a whole world of education that they wouldn't even have had the opportunity to hear of until middle school.
Kinda off topic, but just wanted to shed some light on an unfamiliar territory to many.