My outfit

I would like to point out it wasn't bothering anyone is class at all. I actually got multiple compliments on it to be honest. And we were all sitting and reading the whole class time. It isn't like I was throwing my hands in the air and leaning all around and trying to show more skin. My outfit today was khakis shorts which aren't tight at all and a good length for school and then the big deal was my shirt. For a shirt I had on a light pink bandeau that is lacey and covers a good chunk of skin longer then your middle finger, about half your hand all the way around Then my shirt has open sides that tie at the bottom. It is NOT a crop top or extremely short at all. You can literally only see 3 inches or less of my side. MY SIDE. Less skin is showing then the bandeau is covering. I literally got called to the office because my side is showing folks. My side is too scandalous for school apparently. Not to mention the shirt isn't like low cut or anything its high all around and goes up past my collar bone and has a top of like a t-shirt and its floral print. I have watched a girl everyday at school since it is warm out either one, wear shorts so small her ass hangs out and like a small tank top or wear a crop top with low rise jeans. Now I would like someone to please explain to me why that is okay that someone at school can have there whole butt hanging out of there shorts and have there whole entire stomach showing but I can not show my sides. It isn't like I am just wearing a bra either. It is a bandeau that covers like 5 inches all the way around. I also know a ton of other girls who show so much cleavage. If my side bone is more distracting then cleavage in school then I don't even know what to say anymore. I would also like to explain that this week and past weeks I have not worn anything inappropriate. One day I had jeans and a full shirt one and another I had shorts and a sweatshirt on so if someone wants to tell me what's wrong with that because I would love an explanation.
If anyone can explain to me why what I am wearing isn't okay and what the half the girls at are schools wear then I wouldn't make a big deal of it. School policies are being ridiculous and I am furious. I am a naturally small person and if can't show my side at school while I am constantly seeing other girls bottoms, cleavage and stomach everyday and they aren't getting in trouble, something obviously needs to change. I would understand if schools called me out about my shirt if they were also targeting everyone else who is wearing worse stuff then me, but until they change that I will put of my guard about this and not be targeted when there is worse going on. It really just depends on the teachers you have and they are the ones who report your outfits which isn't fair because some teachers don't care at all while others are super strict. Now I have learned though, what class to wear a jacket in so I don't get nailed. I wish schools could understand that there is worse out there at school and the ones who get in trouble for the small stuff is sad because they aren't solving the real problem.