It’s really not intended as any sort of slight. It does come down to practical concerns and is to a great extent based on where the War Memorials are located - the main British memorial to the Battle of the Somme is at Thiepval, which is why they have ‘ownership’ of that site for the centenary commemorations. Australia’s main memorial is at Fromelle, so that is ours. New Zealand has its main memorial at Longueval, so they have responsibility there. Canada’s is at Courcelette. There really is an intention to allow each nation to commemorate its war dead. And it has to be remembered that all these places are in France - which also therefore has an interest in what happens there. Whatever jokes we may make about the French (and I certainly have) they are very generous in allowing access by foreigners to these sites, but they do ask that the governments of those countries keep things manageable.
I understand, but that means that the communication from those “arranging” the stuff need to ensure that these types of tradeoffs and decisions WILL be made and then when those that still complain do so - that prior announcement should be well exercised and not underplayed.
People who’ve been told the rules - when they have - should not be allowed to then moan and groan about them.
Good heavens if those who fought in these battles had acted in this way we’d all be speaking German (not to sleight those germans who bravely fought for their own country).... but instead to sleight those who should look to their predecessors sacrifices. After all the memorials and commemorations are to acknowledge and consider what THEY did.