The midshipmen who were quoted in the article characterized the synthetic marijuana as "widely used" and "popular among rank and file mids."
The midshipmen quoted in the article were ones who had left the Academy or were otherwise at least tangentially connected to spice usage. They're not necessarily a representative sample in the same way that polling the track team on whether they think the PRT run time is hard isn't representative of the entire brigade. I would not necessarily take their words at face value. The information in this article has been rumor mill at the Academy for a couple months now. The rumor mill is not 100% accurate. Think about it: what agendas and biases might they have for wanting to make it sound like there's more people involved than there actually is?
Semi-full disclosure: I know the (now former) midshipman who had seizures. My company lost people over this, and it sucked even though they deserved to get kicked out. I have not done spice, and neither have any of my good friends. It is not as widespread as this article makes it out to be, but it is a problem.
The investigation is ongoing and there definitely will be more people leaving. Will everyone who ever tried spice get kicked out? No, in the same way that not everyone who drinks underage, has sex in the hall, or jumps the wall gets caught.
Every time something like this happens, people flip out and think that it means the Academy only produces drug addicted rapists or something. It doesn't. Mids are kids, and they sometimes do stupid things. Mids have always done stupid things, and always will do stupid things. That's not giving them an excuse, it's just strange to me that people are still surprised by this.
Trust me, I don't need a "wake-up call."