Mod 80
you can’t compare the two. a cross is a clear, indisputable symbol of avodah zara. Jeans were originally created for functional purposes, and in modern times, can sometimes be designed to be pritzusdik and untznius.
Wigs can be used/designed for pritzus too.
Someone else already mentioned women’s tops that are made tznius by adding shells or whatever. Long jean skirts that themselves were not intended for pritzus should be less controversial.
Pacman
Levi Strauss invented jeans as a direct result of his being non-observant? It came about as a product of secular ideals? No. Why are they goyish? Like someone else pointed out, what many consider frum garb these days was designed by goyim and were adapted from secular culture.
The burden of proof certainly lies on those who declare denim untznius.