Because the risk has not been qualified, nor quantified.
Because a knee-jerk reaction driving textiles in another direction is also an unknown gamble.
Wool wool blah blah... the bottom line is that wool cannot put clothing on several billion people. I love wool, I have much wool but it is no solution to the problems caused by our need for the mind-boggling number of petrochemical derived products. When natural materials were the only available building and heating supplies the tiny human population at the time stripped our country of most of its wood, peat and so on. Why on earth would anyone think it's still a good idea?
Wool is great but people just don't think about how much room a sheep needs to graze and how expensive it is to grow one in a kind humane way... everyone in cheap woollen clothing? That will be intense and cruel factory farming - everyone ok with that?
If people aren't putting forward a solution, they're doing nothing but flapping their mouth parts. Of course any kind of negative human impact on the environment is a bad thing but are we not part of the eco-system? Do other animals dig holes to take a crap in or do they just let it wash away in the first storm or let the beetles and flies have it? We need to take care of this planet for sure but always the knowledge of the future proves the current thinking to be harmful and wrong.
People in electric cars charging from a socket on the wall? amazing, look, no pollution! Oh... coal power station... well, never mind.
So lets stop using fleece jumpers along with everything else bad... and all just die out. Epic solution.