At least in the US, I doubt many of those homeschooling their children do it because schools in their district are "bad."
Homeschooling takes a lot of resources and it would be a lot easier to move to a better school district than to stay in a bad one and start homeschooling.
Do you know of a school district in the US that isn't "bad"? They are all bad. At least, they are all bad if you don't want to raise your child(ren) to be radical leftist revolutionaries. Some people don't want their children to follow in the footsteps of Mao or Stallin.
Critical race theory is taught in all US schools. Fuck whitey! If you are white, you should feel ashamed. If you are non-white, you need to hate the white devils.
Have you taken a look at "common core math"? It took a few months of studying this method of teaching to really understand it, and I concluded that it is purposly designed to make the next generation dumbed down - smart enough to run a cash register, but not smart enough to do any real engineering, chemistry, or science. I challenge you to examine common core math and come to any other conclusion.
Critical race theory and common core math are just two reasons why parents want to homeschool, and it is not possible to move to another district to avoid these nationwide toxic teaching methods.