Oh trust me, if they could enforce the block at the browser level they would. We're well past the start of the slippery slope here in France when it comes to surveillance and control.

I started with telling ISPs to block websites at the DNS level. The people started using 1.1.1.1, 8.8.8.8, 9.9.9.9 and so on. So now they pressure those third-party DNS providers to do the same. This is why 9.9.9.9 is now unavailable here: they stopped serving France because they did not want to comply.