Honestly, it doesn’t bother me at all, and I can’t personally imagine being offended by it. I can see why in our society people might find it unusual, because we tend to do everything involving genitalia in private, but if that isn’t practical or it’ll take literally two seconds to sort things out and be comfortable, I don’t see anything wrong with someone doing that in public. If a body part is uncomfortable and someone needs to adjust it, then they should just get on with it and do that, and I really couldn’t care less if it happens to be a part that is associated with sex or waste disposal. I’d sooner someone attend to something real like physical discomfort than care about something socially constructed and artificial, and sit there uncomfortable, because it’s considered “rude”, “offensive” or “inappropriate” or to draw any attention whatsoever to your genitalia in public. It seems even more ridiculous, because in most situations I can always just avert my eyes if the behaviour did happen to offend me – I’d sooner that than some poor chap have his ballsack stuck to his leg on a hot day or some woman have her boobs chafed by her bra.
Just out of interest, why do people think it is “gross” to touch your penis, testicles or breasts because they are uncomfortable, if you are in a place where other people might be able to see? I’m not trying to be contrary, but I find this really interesting.