Fashion changing all the time (on the order of seasons rather than years) contributes to a lot of waste. Your claim that it "factually something that provides value to society“ is unsubstantiated. Just as unsubstantiated as "You are certainly entitled to the opinion that fast fashion is not a good thing".

All fast fashion does is waste money for consumers who buy into the craze, compared to buying quality that lasts. I have used the same two pair of jeans for over a decade at this point for example, and they are in close to mint condition (apart from the colour on the knees). Some T-shirts that I own have survived as long, many have not (it is very hard to tell the quality of the fibers up front unfortunately). In all cases, I use clothes until they are so worn through that they are past my repair skills.

So yes, some people are "invested" in fashion, but I'm saying that is akin to being "invested" in gambling or shopping for the sake of shopping. Addictions come in many forms.