You're not going to find anyone here who supports, them, or can make a case to support them.
1) No one is asking those questions. Because if they do they'll get primaried.
2) Ill answer this below
3) It does no good, but they're brainwashed into pulling the R lever because liberals are evil.
4) See point 1.
Lets look at point #2, which I think will make everything else make sense. Public schools have things they have to teach. And more importantly, things they CAN'T teach, specifically religion. But also, soon, things like slavery will be off the table. Science...man, that can often get in the way of believing in Jesus. Exposure to ethnic diversity, different people, critical thinking...that shit isn't helping anyone in their view of religion. If you want to teach your kids that the law of the Bible should rule the land, and that not all people or religions are created equal, the only places to indoctrinate that line of thought all day every day is in a private school or in a home school.
And if you have christian nationalist views and tendencies, and you believe that the only future of this country is one run by Christian (white) men, an increasing minority, well, you're going to have to make some drastic changes to what people believe, and how they're made to believe it. Pushing more kids to religious education while shattering the education of a majority of people in a state, well, that's a great way to kill two birds with one stone, imo.