It's not a workaround. A workaround wouldn't solve the original problem: getting an education. Homeschooling does that.
"It's not a solution, it's a workaround" is used when one does not wish to allow solutions that reject the current system, in this case education by the state.
That's a solution for you, but the education system would remain broken for everyone else. That is bad for the country as a whole. Thus, home-schooling your child is a work-around to the bad state of education, but the solution for all children is to fix education.
You assume that education for most must be done by the state. Yes, what I stated is a solution, and it does work around the state education problem. I admit the possibility that the state education system can be fixed, but I also admit the probability that it won't be in my lifetime.
If you have a problem, and you can use a different infrastructure to avoid it at an acceptable cost, it makes sense to use it.
"It's not a solution, it's a workaround" is used when one does not wish to allow solutions that reject the current system, in this case education by the state.