That's like saying a society where some people are free and some people are slaves is more free than a society where everyone is free.

I understand the concern of making Windows available to children, but in the end, it is better than no PC at all.

If it was a choice between a PC running Windows or no PC at all, ever for the rest of someone's life, then I'd agree. But as Stallman says "Teaching children to use Windows is like teaching them to smoke tobacco—in a world where only one company sells tobacco."

In fact, why not dig deeper. Is the CPU Open Source? Why is it not a problem to use proprietary hardware?

Actually, Windows does not even have that much of a lock-in, or does it? The lock in used to stem from MS Office, and even that is not so severe anymore these days.

And I think for those children it was a question between no PC or a Windows PC. If for whatever reason the government or whoever pays for the PCs says so, what do you want to do against it?

Of course not. I didn't say it was.

Is the CPU Open Source? Why is it not a problem to use proprietary hardware?

Open Source processor designs exist. It wouldn't surprise me if in future FLOSS operating systems run on them.

I don't consider proprietary CPUs to be a big problem -- though they would be if they were running some sort of Treacherous Computing system or DRM which meant they wouldn't do what the user wanted.

Windows does not even have that much of a lock-in, or does it?

The lock-in is vastly less than what it used to be. I can develop web applications using a GNU/Linux system with no problems.

If for whatever reason the government or whoever pays for the PCs says so, what do you want to do against it?

It's not for me to tell foreigners how to run their countries (it's not my country). Though IMO if they make themselves dependent on Microsoft, they are not acting in their own best interests.