Though I know what this is for, but I am against blocking VPNs and Tor since it prevent privacy-conscious people like me and other people such as dissents or other having high risks of like harassment online.
The instances being affected the most are those with open registration, and don’t block registration from temporary email providers, and have don’t have like automatic filter or using Fediverse softwares not providing such.
Though given Lemmy development may not support blocking registration by emails or filtering keywords or filtering federation of very new accounts/new account having no profile, manual approvement registration or applying bots filtering repeating spams may be enough without blocking VPNs or Tor I think
I think even ChatGPT would eb called non-free for them though