“While Canadians did fight under the Red Ensign during both World Wars, and in Korea and other smaller conflicts, it was not a National Flag.”
It was the national flag. It was flown at Rideau Hall, etc. The situation and the debate in the 60’s is exactly the same, for the exact same reasons between the exact same camps.
Sure, they had the right to change the flag - but should they have changed it? Absolutely not. Neither should Australia. What is Australia without her heritage?
No, it was not. It was never gazetted as such, nor proclaimed as such by the Monarch (or the Governor General in the name of the Monarch).
Australia's flag was proclaimed as a National Flag by King Edward VII on 11th February 1903, and Gazetted as such on 20th February 1903, after about one and a half years of unofficial use. Neither of these steps ever took place for the Canadian Red Ensign. It was used on the basis of Orders in Council by the Canadian government but those orders did not create a national flag, merely something to be used as an alternative when confusion would be caused by use of the Union Flag alone.
The Maple Leaf Flag was proclaimed by Queen Elizabeth II on January 28, 1965 and gazetted as such on February 15, 1965, the first time these things had been done for any Canadian flag, and that's what made it an official National Flag.
I'm a retired protocol officer of the Royal Australian Navy. These distinctions were my bread and butter. They don't matter to most people in most cases, but they are important in some situations.
Put in another way - you could argue that the Canadian Red Ensign was a de facto National Flag from around 1892 onwards, but you could never argue that it was a de jure National Flag. In the case of Australia's flag, it gained de facto status as such on 3rd September 1901 when it was flown over the first Parliament of Australia - but it also gained de jure status on 20th February 1903.