It has nothing to do with it. In fact, I find it extremely ironic because graduating from a school stands in stark contrast to yelling that phrase.
I attended a graduation this year. The Principle gave a polite, and reasoned talk on respecting the other graduates so their families could hear their loved ones names called too. Fuck it, some gaggle of rubes gonna show respect to anybody else? Fuck no! They dont give a fuck and moreover do it so people will look at them. They need the attention. And all they're doing when they whoop and holler for a HS graduate is proclaiming to the world either: "This is a major life accomplishment in our family, and likely the highest accomplishment any of us will ever know" or "Yippee! This fucking dumbfuck kid barely made it out of a shitty public school, and we got his bags packed and waiting on the trailer's redwood deck for him so there's one less mouth to feed, we've done our job, now he has to find his own way".
At the one I went to this year, it held off til somewhere in the B's or C's. All the Valedictorians and Honor's people that went first went through without a peep, again, because they have higher aspirations in life and come from family that do too. But, following the first group willing to break ranks, each subsequent idiot family got louder and louder so as to outdo the previous.
Now...