Help! My little sister is heartbroken

[TianaKay]

My younger sister wants to be an AKA more than any high school senior I know. However, when our parents heard about some of the goings-on at my school, they forbid my sister from seeking membership in any GLO.
The Omegas threw a huge party last month. There were some AKAs, Deltas, and Zetas there. By 1:00am some of these sophisticated sorors looked more like video chicks! Two AKAs got into a brawl with two Deltas, and they all looked like hoodrats! One brave AKA stepped in to break up the fight, and one of the AKAs who was fighting spit in her face! They're from the same undergrad chapter!
As if it couldn't get any worse, I have a class with three of these Q-Dogs, and some of their friends. They showed me some of the cellphone videos from the party. I was near tears! I was embarrassed for these sorors! I saw some of them around campus the following week. None of them gave a s**t that there are videos of them doing strip teases, giving lap dances, and performing oral sex. My twin brother's classmate keeps bragging about having a full-on sex video of him and one of the sophomore AKAs!
I still have a lot of respect for Alpha Kappa Alpha. Overall, you are beautiful, intelligent, well-rounded women. However, I have to ask: WHAT'S GOING ON?! It seems as though being an AKA doesn't mean what it used to even five years ago to SOME of the younger members.
If someone could please offer me some advice on how to convince my parents that if they support my sister seeking membership in Alpha Kappa Alpha, they're not throwing her to the wolves! My little sister is intelligent, out-going, spiritual, and very giving. Committing herself to public service would be easy for her, and enjoyable. She all ready tutors middle school girls. I KNOW Alpha Kappa Alpha does so much good for so many. I want to prove to my parents that Regardless of what a few misguided sisters do, you ladies are truly phenomenal!