Why the debate around Australia Day gets more heated every year

A protester waves a flag during an "Invasion Day" rally on Australia Day in Melbourne on January 26, 2018.

(CNN)"This used to be the greatest country on Earth, but we've lost the plot."

It might just be a commercial -- Australian Lamb's annual advertisement ahead of Australia Day on January 26 -- but it's struck a nerve with a lot of Australians this year.
As Australians deal with a record-breaking heatwave, environmental devastation and a sixth prime minister in just over a decade, the annual fierce debate over the country's national day might be the thing that pushes many of them over the edge.
    Australia Day is held on the same date Britain's First Fleet sailed into Sydney Harbor in 1788, beginning the European colonization which led to the modern nation of Australia.
    Not everyone sees it as a reason to celebrate. Aboriginal and Torres Strait Islander people see the date as the beginning of the deliberate destruction of their people and culture as colonists took lands they deemed "uninhabited" despite large indigenous populations living there.
    Many Australians refer to January 26 as "Invasion Day."
    The controversy has led to a growing push to change the date of the country's national celebration to another day without the historical baggage. Few former British colonies celebrate their national day on the actual day of colonization.
    But a group of conservative politicians led by Prime Minister Scott Morrison have pushed back hard, saying they will protect Australia Day and ensure it is respected.
    "I'm not just going to not change it, I'm going to ensure it doesn't get eroded ... That's our historical day and we need to work together, to come together on that day to ensure that we can make it an important day for all Australians," Morrison said earlier this month.
    People take part in an "Invasion Day" rally on Australia Day in Melbourne on January 26, 2018.