If you home school, you don't get the money back. Public school is something like $12k/yr. That's a lot of money that you're essentially opting out of. For parents who do so for political or culture war reasons, that must seem profoundly unfair. To be driven out of the public schools means to be denied resources. Public schools using public money should be especially sensitive and as neutral as possible on political…
Money spent ≠ value provided. My kid's class has over half a million dollars spent on it per year. But many parents see it as merely childcare, and then spend more money on after school tutoring and activities.
I can see the appeal of skipping the schooling and doing the other activities during the school day. It's probably much easier/cheaper to get appointments before 2, when most kids are in school. And there's more flexibility in terms of scheduling. I just heard today that a family was threatened with being kicked out of our local school if they accrued 10 days of unexcused absences (which includes vacation days). While I don't think the school would actually kick the family out, the fact that this is even floated as an idea sounds crazy.