Nobody: denim is not connected with a goyishe form of dress. I don’t know where you get that idea from, but it’s wrong. Many people where denim, both Jewish and non-Jewish. I’ve been over to my Rebbe’s house and saw his wife wearing a denim skirt.
Wearing ripped, frayed jeans made especially that way is a different issue – not because it’s goyish, but because it doesn’t look presentable. You can look presentable in a normal pair of jeans.
I usually wear jeans on weekends because I do some work around the house. Jeans are comfortable, durable, and wash out easily. Do they get faded? Of course, all clothing does. The difference is that with other pants, as they fade, the material wears out also, so they don’t reach a point where they’re really faded. Jeans last longer, and can reach a stage where they’re extremely faded out.