I still can't wrap my head around why a DNS provider is required to block websites, especially one that is not associated with ISP or used as default on any device. Oversimplifying this, it's a glorified hash map, so whoever wants to take down the illegal content should just deal with the website owner?

I think a large part of it is the tech-illiteracy of world leaders.

I'd wager that a lot of the folks implementing these policies don't know the difference between a DNS server and a VPN. They think DNS=VPN, so all the hackers are using cloudflare to get around restrictions.

In general, most folks who use the internet don't know how it works and they don't want to know.

Let's say our dear politicans view most illicit contents as nails, and view DNS as a hammer. Unfortunately they are now aware that people can trivially get around the ISP restrictions by using another DNS provider, and have started to pressure third-party providers to apply the same blockings as the ISP ones. This is why a few "neutral" providers have outright blocked France because they refuse to block websites.

aren't we all just glorified atoms

Presumably they have failed to do the latter and are just reaching at this point.