Honestly, in this day and age I consider VPN a basic internet hygiene. There are many many reasons to not trust your ISP and the wire between your home and ISP. You have moderation here, why do you even need to block VPN? I registered this account from VPN, but I somehow cannot comment from VPN? Doesn’t make much sense. I’m using paid Proton VPN servers, and btw I’ve seen Proton having a dedicated community here on this platform.
Yes, that is a problem. No single solution is perfect, and VPN blocks are only one tool in the toolbox. Every instance is different, and admins pick the tools that they think will work best for their situation. VPN blocking happens to be a tool that seems to have worked well for lemmy.world.
Instances that lack moderation and have a history of being used by trolls tend to get the nuclear option: they are defederated by the big Lemmy instances. That’s not ideal at all, but the tool set for Lemmy moderation is very limited right now.