I think we should differenciate between the shorts the men usually wear for floor and vault, which are not tight fitting, and the tight, spandex shorts female gymnasts wear for practice.
I feel like the men version does prevent the judges from seeing splits angles. It could also be a safety issue on bars (during hip circles in particular). The spandex version, however, are just fine. As a judge who trains in shorts every single day (and so do my teamates), I can see lines, handstands and split angles just fine.
I am very much in favor of shorts being allowed both in practice and competition, as long as they are stretchy and tight fitting.
I don't care about the colour. I don't feel that black shorts look particularly bad even with a coloured leo and gymnasts should not be judged on their look anyway.