You’re completely missing the point. We’re not talking about the art assets at all. This issue is that the text (about the source code, not about the art) is contradictory: First it says the code is “Public Domain”, but then it says the code “is for non-commerical use only”. But this is a contradiction. If the code is public domain you can’t impose any restrictions, which is what “for non-commerical use only” is.