I actually have one of these on the emergency kit my brother gave me for a car, he put it together in a like military style bag to keep in my trunk and it has a patch on it like that. It’s just a monochromatic version of the American flag, anyone I’ve known who has something like that doesn’t intend anything past that. Like others referenced, modern fatigues and gear in the US Military feature a similar monochromatic flag to that (usually black and the primary color of the uniform, like desert tan or olive drab) to save cost and make it blend in with the uniform better, so I think that popularized that to some degree in culture.