Because the English people were and England were involved in that war.
In WW1 in Turkey
World War 1
How many Australians were involved?In Australia it was estimated that 993 000 men and women were involved in WWII
that is the first place that the Australians fight war
they weren't fighting
to be remembered
Several in the Dardanelles. (See Gallipoli). In the Pacific, German Samoa was taken over by NZ troops without casualties, and Rabaul at Papua, New Guinea was taken by the Australians with minimal loss of life.
The Gallipoli landing occurred soon after the onset of World War I.
Many of Australia's indigenous people commemorate ANZAC day with the same respect and solemnity as other Australians do. After all, many Aborigines have served in wars in which Australia has been involved, since the Boer War, which was well before World War I and Gallipoli. see the related link below on indigenous Australians who have served in wars.
Hitler was not involved in the Battle of Gallipoli. He served on the Western Front during World War I as courrier for the German forces.
the importance and consequences of gallipoli war
OP, go watch the movie Gallipoli. That will give you a good idea of what the ANZAC forces went through in WW I aka "The war to end all wars."