Thanks for the link, I wasn’t aware of that discussion. The lemmy.world terms of service says:

Users are allowed to use any provided method to interact with Lemmy.World, as long as it is in good faith. VPN and/or Tor access is not explicitly disallowed, however, we reserve the right to restrict and/or limit types of access via anonymizing services to protect both our site and staff.

It looks like lemmy.world does not proactively block VPNs, but does block IP addresses that have used lemmy.world abusively, even if blocking the IPs would cause other unrelated accounts to be affected.

All I can say is that I’ve never been affected by such a block. But if I do get affected, I’ll switch to a different instance or even a different service such as Piefed and Mbin.

lemmy.world does not allow the use of vpn to post.

That is definitely not true. I’m using one right now, and there is a VPN community at !vpn@lemmy.world.