If you had read the article before commenting, you would see that it’s not about a blanket no-war-ever-at-all sentiment (though of course per the quote there is some pure pacifism). As examples:

However, Throssell’s anti-war views, derived from his firsthand knowledge of war and its consequences, were largely ignored.

This pattern repeats across Australian history, from the first world war to the War on Terror. In every war, there have been a number of soldiers and veterans who turned against it, Some became pacifists, while others acknowledged the necessity of war in rare instances. They drew on their war experience to caution restraint, urging war-makers to reflect on Australian values and interests before committing Australian lives overseas. (emphasis added)

Several International Brigade veterans went on to serve in the second world war, to continue their anti-fascist effort. Jim McNeil enlisted at the outbreak of war, just nine months after returning wounded from Spain. He and others like him “just hated fascism and wanted to fight it”, he explained.

These stories show not all radical veterans became pacifists. Some recognised the necessity of countering the extreme threat fascism posed to Australia, at home and abroad. (emphasis added)

In each of these cases, the protesting veterans were explicit that their opposition to war was about protecting Australian interests and values. Mansie, for instance, argued the Iraq War would “incite terrorism” and endanger Australians, something security experts agree was a lasting consequence of the War on Terror.

He also argued involvement in an illegal war was not in “the fighting spirit of our nation and its defence force personnel”. Like those volunteers on the International Brigades in the 1930s, Mansie invoked the Anzac legend to support his position, framing Australian warfare as defending fairness and righteous causes. (emphasis added)