I think properly funded schools with properly paid special needs instructors would leave far fewer students behind than allowing homeschooling.
True, but what if that's not the choice being prevented? What if the choice is between not between individually sought resources and state provided resources, but between individually sought resources and none at all? Should we really deny people without access to decent school systems the right to pursue other options?
I believe good public schooling is better than home schooling. But the solution isn't to ban homeschooling. It's to make the public schooling better. In many places, public schooling is very very bad, and it isn't going to get any better any time soon.
And I don't think we should be so quick to deny people their rights just because they believe things that are different from what we believe.