Do you seriously think that public schooling is actually going to give children exposure to this "undesirable beliefs, classes and ethnicities" that you speak of? That kind of public school is a mythology. Public schools are by and large 1) socioeconomically homogenous, 2) racially homogenous (among one or two groups), 3) class homogenous, and/or otherwise culturally homogenous. And even in schools that lean towards heterogeneity rather than homogeneity, it's not like all the kids are harmoniously integrated into one happy family. Schools are dominated by cliques and social circles, and stereotyping is rampant. A kid in a school with Asians is going to come away with the stereotype that Asians are nerds. A kid in a school with African-Americans is going to come away with the stereotype that African-Americans steal things. And while that might not be the case in all cases, I might argue that it is as representative as your belief that homeschooling parents are "controlling," etc. etc.