@Rickoshay75,
I don't think it is the fact that one is more important or one is more tragic than the other -- it is the murder in France was a terrorist attack and an attack on the freedom of the press. The murder of the children was an attack by an insane person.
I think the walks and such are showing support of the fight against terrorism and the support of the freedom of the press/freedom of speach.
And there was alot of support for the children as well -- just shown differently.