This is already impacting futurology.today - one of the Mods is British, and because of this law doesn’t feel comfortable continuing. As they have back-end expertise with hosting, if they go, we may have to shut down the whole site.
How easy is it to block British IP addresses? Would that be enough to circumvent any legal issues, if no one else involved in running the site is British and it is hosted somewhere else in the world?
Does it really, practically, impact things?
If people had to obey the law of “every country that has any internet presence”, site operators worldwide would have to do such silly things as ban women from using the internet while not sitting right next to their husbands, or who knows what other silly things as per the Sharia. So I don’t really see how any such thing is to be taken at anything but grandposturing from boomer political parties, at face value.
Now, if you want to ban Bri’ish IP addresses, your hosting can take care of that. For the most capable ones it’s just a flip of a switch. But do consider that in some cases that makes your site worse for everyone else worldwide as such rules are sometimes implemented via privacy-invading systems (eg.: yet another control that makes your site depend on Cloudflare).