...School is not synonynous with education.
We do know there are many countries in which attending school is unattainable for the average child. That there are places which restrict schooling to (cisgender) boys and men. That there are places in which even basic primary school costs a small fortune and isn't paid for by taxes.
But it's flat-out wrong to say that the issue is access to the school itself. The issue is access to education. In a lot of places, a school is the only reasonable way to achieve that, because of a variety of factors. Sure! But you're misinformed at best if you think that all schooling systems everywhere actually give a shit about education.
A school does not necessarily educate. Schools do not necessarily create a functionally literate population. Schools do not necessarily help children grasp basic academic skills. Schools are institutions with an inherent power structure that make children extremely vulnerable to serious abuses. Schools can create environments which actively inhibit education.
Risu is a home educator because he looked at a system which was causing his child stress to the point of attempted suicide and made the decision to remove it from that system. He is providing his child with an education. He is simply doing it in a way which insures his child is actually alive to receive it.
Education is important. But it's not as important as a happy, healthy, living child. And schools cannot guarantee either of those will happen. In fact, in many places, they are far more likely to do the opposite.
Every child deserves an education. The UK schooling system is not providing that. Risu is. End of.