I strongly disagree and despise this kind of thinking. Don't get me wrong, OSS is awesome for tooling (shared by many creative professionals) but not for end products. An architect's tools can be open source, but an architect's plan is their own creative output that should not be open source if we make this analogy. Architects can get together and build better tooling for the benefit of all architects - OSS shines here.

This project is a creative output. Stop for a second with entitlement to the source code and just enjoy for what it is and how amazing this project is.

Do you go to museums and ask for what color palette the artist used? It's missing the point, isn't it?