You have the definitoin of chukas hagoyim wrong-its not doing what the goyim do! cuz then we wouldn’t be allowed to breathe and chew normaly because that is also how the goyim do it! From what I remember, chukas hagoyim is doing something that the goyim attribute to avodah zarah-im not 100% sure on that, I have to go check.
Why are we talking about chukas hagoyim though-i thought we were talking about shorts being tznius or not?