I just finished reading a very good book on the D-Day landings in 1944. 100s of Allied troops died that day from 'friendly fire', many from short rounds from ships off shore.
In every war there are casualties from FF, perhaps the US kill more because they are always in a position of delivering the majority of the ordinance.
The only thing new about these sorts of mistakes is the advent of CNN......and therefor public awareness.
It's sad but I would suggest it is just one more aspect of warfare that, pre Vietnam War, the public never knew about.
All the platitudes from the generals and pollies, the 'investigations' etc are, imho, just window dressing on a problem that will never go away while ever wars exist.
Chuck