Well, chicken finger kid got a suspension and sent home for the day. Pop-tart kid got a suspension. Only the Dinosaur Hunter (who interesting, is also the only other teenager on this list) got arrested. And Dinosaur Hunter (in theory) actually *did* talk about guns in school.
So for why, I'd give a couple reasons:
Clock Kid didn't even *do* the thing he's accused of. Which moves us up a rung from "massive over-reaction" to "teachers and cops are just making shit up".
There's some escalating reaction from the community as things just get dumber. Dinosaur Hunter's article even references PopTart. So, every time we hear about this sort of stupidity, you get just a bit *more* angry - which we should, because it gets harder to write it off as "oh, just an isolated incident / overzealous teacher".
To be a bit cynical and flippant for a moment, Dinosaur Guy was doing a creative writing exercise, and no-body cares about liberal arts in America. Meanwhile, Clock Kid may be a case of chasing away a potential STEM graduate (you know, future of the nation, shortage in the country, etc etc).
Also, he's getting a lot of attention from geeks who are watching this and thanking our lucky stars that we didn't grow up in this period. Half the stuff the teachers had us do in school in the 90s would get us arrested these days, I'd think.