I personally feel like negative filters are important because they create an incentive for advertisers/SEO/etc people to not spam every keyword into their product.
If you're only allowed positive searches, the best way to get your product found is to maximize the number of positive search terms associated with your product. With negative search terms, every additional term you add is a potential exclusion criteria as well.
Unfortunately, people just don't use the negative search terms enough, so it is up to the search engines themselves to detect metadata bloat, and that ends up being a cat-and-mouse game.
If you're only allowed positive searches, the best way to get your product found is to maximize the number of positive search terms associated with your product. With negative search terms, every additional term you add is a potential exclusion criteria as well.
Unfortunately, people just don't use the negative search terms enough, so it is up to the search engines themselves to detect metadata bloat, and that ends up being a cat-and-mouse game.