In many countries, it is possible to force ISPs to block content - and in the end, I guess it's easier for ISPs to simply not offer you their service, than face gov. mandated fines.

It's a bit like cryptocurrencies and banks. Because it becomes such a big burden for banks (to prove that the money obtained by selling crypto is not related to funding terrorism, crime, etc.), many banks simply refuse service to customers dealing with crypto. Either closing accounts, freezing money, or whatever.