Folks are free to submit forks of WGTunnel, yeah. I believe something similar happened when NetGuard was pulled from F-Droid (ex). The various SimpleMobileTools apps were also hard forked wholesale by Fossify (why). A few apps are already forks of their originals, like Intra.
What F-Droid now wouldn’t do is track the original repository for releases anymore, at the request of the lead developer.