It's a Catch 22. If the schools don't maintain standards, then people complain that the public schools are cesspools and nobody is learning anything. If they have a requirement like this, some people will complain it's an infraction on the rights of parents.
I personally think the public schools are only responsible for the basic skills to be a good citizen, get a job, and function in society. Parents should have to demonstrate their students have achieved this much, so the children are prepared to function in the adult world.
In these cases, though, more should be required. I don't know if this came up on the thread. These home study students who keep up with an approved plan graduate with their classes and have a public school diploma from that local school. So, of course there have to be some assurances that the student isn't being given a gift, sitting home and not up to the same level as students in school.
The alternatives? Private schools, GEDs, and Junior/Senior year in a public college.
I would agree with the first statement but find government schools somewhat lacking in that achievment. You and I will just have to agree to disagree on the second statement. You are accepting of the premise that all citizens should be obligated to demonstrate parental fitness to the State by way of educating their children to State mandated standards. I will readily admit that the majority of people now accept just that. I sure don't.
IMO the turning point for the worse in education can be marked by that point where people let the government take responsibility from them. I advocate taking it back.