Its probably because there are too many battles to remember.
And while I'm on,personally I think we have too many of these quasi remember this or remember that days. I get sick of them. The wars long over. The fighters are practically all dead. That generation has gone. I thanked them repeatedly when they were alive, but they are nearly all gone and its time to move on. Keep it simple, have 1 full day of remembrance in November (like we used to) and move on.
We glory in this too much, at times. Recently, it seems all the time.