I just watched the live broadcast - here's my view on it, for what it's worth.
It wasn't anything more than a pep rally, geared toward middle schoolers and above. Children younger than that, I'm sure had little comprehension of what he was saying, nor will they retain any of it. And having a kindergartner view it - why???
Unless the teachers of these younger children take the time to go over some of the points on a level that is understandable to them, then it was pointless for them to even view it.
Get with the program Mr President. You can't talk to a first grader and a senior in high school on the same level. :( Your intentions may have been good, but your delivery was sadly deficient. :p