It's not the celebration that's being questioned, it's the nature of it. There's a big difference between an end-of-year party and a "graduation ceremony".
Sure, at an end-of-year party, you mill around etc., while a ceremony is structured, and gives time to recognize, celebrate, and remember every child.
I guess it gets more diluted with bigger schools, but at the early ages especially, the schools can be small, and every kid can be known by everyone.
Just came from both -- a ceremony and a party, and it's no contest -- in the party the parents talk about their kids with other parents directly, and about other things like homes, work, politics, etc., and the kids go off to play by themselves as usual, while the ceremony was entirely focused on the kids ----- where we got to see every one of them do and say something, and see how far they've come with pictures and videos.
If you couldn't spare the time or thought for a graduation, or thought that it was unnecessary because they haven't accomplished anything and are not worth the time and trouble, maybe it's your school or parenting which is lacking?