I read Sewing Eco-Guilt? Killer! and groaned. I left a comment but it didn't appear so I'm leaving my response here.
I'm a scientist and I don't care if you wear polyester or organic hemp as long as you curtail driving and flying (and eat less beef.)
I don't even care if your car is electric. I just want you out of a car.
Yes, polyester is made of fossil fuels, but at least it's sequestered in your blouse. Nothing degrades in a landfill, polyester and natural fibers alike. The important thing is to cut down on our consumption.
I wrote a blog series about sustainability and sewing. It has links to actual data.