I think that this is all about trying to get Democrats elected in November. The fact that the school systems were strongly behind this suggests that the Teacher's Union is deeply involved, and the lack of any meaningful proposals to, you know, actually address the stated problem is pretty telling. The kids are, well, kids - blathering empty nothings for the camera, nothing more.
As the Bard said, it's a tale told by an idiot, full of sound and fury, signifying nothing. Keeping people hyped up seems to the the only thing. You don't need well reasoned policy proposals for that.
I also don't think that this changes anything about the poor chance of any new meaningful gun control laws. The Democrats had their chance in 2009 and (remembering 1994) didn't touch it. I think that they've come to the conclusion that this is an area where they don't want to do anything meaningful, and would rather keep it as an issue that never goes away. At least, I think this is the view of the national Democratic Party. States will continue passing what they think they can get away with, so that's the ball to keep your eye on.
But Keith Ellison and Wayne LaPierre have precisely the same motivation - keep this issue alive and kicking, to keep the donations coming in.