To be clear, articles like this are saying “China”, “Belgium”, etc. as shorthand for the national government of that country.

Not that everyone in that country must switch; only that the country-level government is declaring they will switch computers they use.

This does have a strong effect on what other organisations and individuals use, but it lags a long way and certainly doesn't directly affect everyone in the country.

With that said: Yeah the Chinese government is made up of a great many more people than European national governments. It's a big move.