I agree with Piscesmoon - your daughter should do a bit more reading on this topic. If she is intelligent and mature enough to decide to take a different stance to her school's official line, she is mature enough to educate herself fully as to the meaning and significance of the poppy.
Rightly or wrongly, the poppy, and Remembrance Day as a whole, are more strongly associated with the two world wars than with any subsequent conflict - probably for the simple reason that they were on a massive scale and were long enough ago to have passed into history, with books written about them, films portraying them, and lessons about them. The poppy is about remembering the vast, almost unimaginable, number of mainly young men and women who went out, perhaps willingly, perhaps reluctantly and in great fear, and gave their lives, not just to defend their own country, but to free other nations and ensure that Europe wasn't overun by a truly horrific regime.
Remember that at the moment some of those young men died, having in some cases literally thrown themselves bodily at the enemy to try to gain a few miserable inches of land, they had no idea if their deaths were going to achieve anything at all. In both world wars, the enemy was a massive, seemingly-unstoppable war machine. Many of those young people probably died thinking we were going to lose the war, that their loved-ones back home were going to die too.
Remembrance Day is a chance for us to recognise every one of those young people. For many of them, there was no funeral, perhaps they were not even found to be buried. That is what the poppy is about. Their only chance to be formally remembered.
Whatever I may think about the rights or wrongs of more recent conflicts, I am grateful for the chance to be part of Remembrance Day. There is nothing about it that is a celebration - it's a commemoration, and a requiem mass.