Mr Cameron is keen to get his face on the 'celebrations' for the beginning of the war, because it is highly unlikely that he will be in any position of power in 2018, when a celebration of the end of the war would be appropriate.
You can almost here Call-me-Dave's thinking - WE are the party to add the gravitas and sombre note to this historial time, and hopefully I will go down in history as the PM who thought of it all.
I recall that when Thatcher's government were considering war with Argentina, the majority were against it, for one simple reason. With the exception of Margaret Thatcher, ever member of the Cabinet had seen active miliary service - war was not a concept to them it was a reality, and not one they were keen to assit in repeating.
I wouldn't blame Call-me-Dave for having no direct experience of the horror of war, but I do blame him for looking to make political capital out if it.