I think "community" and "contributor community" are getting conflated here (and I made the same mistake in my original comment).

All of the projects you cited certainly have a large user community.

> To us, it seems ridiculous to see projects with a single developer and virtually no users consuming as much or even more resources than some of the largest community projects on Codeberg, which operate frugal with CI/CD and storage resources. We do not believe it is reasonable for Codeberg to invest our precious donation money into hosting of large ghost projects.

Codeberg is not saying that solo developers don't belong. Codeberg is saying that they exist for projects that contribute to an open source commons, and that spending money on hosting projects that use a lot of resources but don't meaningfully contribute to that commons isn't something they want to do. It seems like their intent here is practical, not philosophical. If servers and electricity grew on trees, they might very well would not have had to even had this discussion.

Another practical application would have been if they would have charged for CI - by the minutes - for projects with no user or contributor community.