Colors on the other hand aren't because you made it (or it's used in China?)
I still think neutrality is important, but gleki brought up a good point on IRC : There's no way to be neutral when we're using someone else's calendar already.
ti'e even bacteria have 7-day cycles. so it might be neutral. Of course we might ask {ma jalge?}. Is it humanity that forces bacteria to follow this worldwide artificial cycle. Or is it nature that forces people to use it's 7-day cycle?