The simplist and most direct method is to address the specific word that was used. It is really irrelevant what that word is. The fact that we would distinguish between a "fun" word and a vulgarity means that we have missed the point. It was the use of the "fun" word that was disruptive. So banning the word becomes an effective tool in eliminating the disruption.
Had the word been a vulgarity we would all ridicule the school for banning it -- right? Of course not. We'd probably ridicule the school if it did not ban the word. So what is different?
Now, on a personal level, do I think that the school made the most rational choice? I don't know all of the facts. IMO there is a lot more going on than just word choices if an entire school plans to disrupt a school activity -- which is what media reports lead us to believe. There are surely serious underlying problems involving teachers, students, administrators and parents -- the entire school appears to be dysfunctional.
So my personal view is that banning a word won't change anything. That doesn't negate the value of the ban in sending a message that the school administration is intent on establishing control over an anarchic student body. But it does indicate that there is likely more to the story than just 'meep'.