I heard them interviewing the girls (one from grade 8 about wearing a spaghetti strap tank top, and one from grade 11 about the booty shorts) on the radio and they both honestly sounded like idiots that just don't understand the rule. They both insisted boys never get "dresscoded" (not a verb), but I remember in high school the guys getting reprimanded for wearing tank tops and having their pants sagging all the time, they just never made a big embarrassing deal about it.
Its not difficult or at all outrageous to expect both boys and girls to keep their shoulders and thighs covered while on school property. You want to wear a tank top after school, wear a button-down and throw it in your back pack once you're out.
These are just silly, selfish girls, being encouraged by their mothers to challenge the rules because they are spineless and permissive in their own parenting. The mother was questioned directly about if it bothered her that her grade 8 daughter dresses in short shorts and has her bra straps showing, and the mom even seemed to hesitate slightly before saying 'oh no no no, of course not,' like it does bother her but she can't say no to princess.