Let me make it perfectly clear-
WE KNOW COTTON IS WRONG FOR TENTAGE.
Buffalo hides for tipis are expensive and heavy.
If you want a linen tent (which is PC/HC), either you pay through the nose to have one made or make it yourself. There are also issues of safety at events due to the flammability of untreated tent canvas. On the other hand, under SPECIFIC circumstances, cotton tentage is accepted due to the previously-listed reasons.
While the newer Russia sheeting is cotton, the proper material is still available, so (other than as a temporary cost-saving measure) we can buy and use the proper material. Also, research and evidence has shown us that a wedge-type tent (with or without a bell) was the most common type.
However, the exception mentioned above does not absolve us of the responsibility to improve our impression if we know and can make the change. I still have a cotton tarp that I use occasionally because I haven't had the time or the $$ to make a linen one. It doesn't mean that the cotton is right, I know it isn't. BUT at $10-20/yard and needing 8-10yds of linen, it is a choice that will need to wait while other more important things are done first.
I have items of machine-sewn cotton clothing that I still wear, because finding the time to hand-sew linen garments is short. On the other hand, I am making all new items of clothing from linen, wool, hemp and braintan to replace the items I have now that I know are WRONG.
The difference is that I know what I need to change. Some people know the stuff is of the incorrect material and/or construction and DON'T CARE. That is the problem.....