It decreases the diversity of thought. If your school system is failing, the government shouldn’t imprison parents who want to do their best to try something else.
Not sure why "diversity of thought" is axiomatically a Good Thing. When extremely religious parents homeschool their children because they want to pass on those values, that's bad for society. Some things are heterodox for a reason.
As a citizen in a country, you get to decide on allowing religious fundamentalists to indoctrinate their children. I choose hell no, keep religion out of schools and out of public life.
This is an authoritarian mindset common on the left but is antithetical to liberal values. Having a desire to control how other people prefer to care for their children usually doesn’t end well historically.
You're using a lot of loaded language in your response. What is a "religious fundamentalist" to you? Also you're missing the point, because the topic of discussion is religious people educating their own kids, not religion in public schools.
Diversity of thought is important for creating a robust problem-solving framework. Once a monoculture forms it becomes easy to subvert it because people tend to be vulnerable in the same way.
e.g. a monoculture is easier to abuse by corrupt leaders. Increased diversity of thought may have prevented Germany from systematically becoming entirely reliant on Russia.
You're assuming that parents who are homeschooling intend to provide their children with a good education. However, what about people who claim to "homeschool" their children but don't actually follow through, leading to uneducated adults who can't support themselves. I think that assuming good intentions for everyone is a problematic assumption, and you need to manage policies for bad actors as well.
