I remember back in the late 60's/early 70's, folks where criticized for using toilet paper in Designer Colors. Claim was that all that dye was polluting our waterways just so vain folks could match their bathroom decor.
Well, the masses responded and the sale of colored TP dwindled.
However, it was found that the bleach used in making TP white did more damage than the dye.
I didn't see any push to go to "natural" TP. Perhaps it is not possible to make the product that way.