"When I was buying my first home, I wasn't buying smashed avocado for 19 bucks and four coffees at $4 each," he told the Nine Network.
The issue has been echoed all around the world - particularly in the United States and the United Kingdom, where newspapers and broadcasters are having a field day at the expense of Australian millennials.
Take the Los Angeles Times, who polled three experts to find out whether young people really are "throwing away their financial future on fancy toast".
Here's an excerpt:
"No, actually," said Greg McBride, the chief financial analyst for Bankrate.com.
"Obviously not," said Helaine Olen, a personal finance columnist for Slate and the author of the book "Pound Foolish: Exposing the Dark Side of the Personal Finance Industry."
"It's absolutely accurate," said G.U. Krueger, an L.A.-based housing economist who has done research for California Public Employees' Retirement System advisors and other investors.
Then, he laughed. "I'm kidding."
Time Magazine jumped on board with a ridiculous avocado toast calculator, asking people to enter the details of their city and state to find out how many servings they'd have to skip to be able to afford a home.
"If you're brunching in New York City or San Francisco, you could be looking at skipping roughly 10,000 and 21,000 avocado toast servings for a down payment, respectively," wrote journalist David Johnson with amusement.
The Telegraph in London dryly observed: "If one ate avocado toast at this cafe every day, and stopped this in order to save, it would still take over 40 years for the forlorn avocado fan to save the required amount for a deposit".
A quick Google search reveals the issue has been reported in countless other publications - including heavyweights such as the New York Times, who pedantically crunched the numbers to prove that while millennials could certainly save some money by ditching avocado toast, it wouldn't actually make any real difference.
In the vast majority of cases, Tim Gurner's comments were taken literally, reported with scorn, and ridiculed on social media.
"Gurner's hot take on both food and finances is garbage," opined Maura Judkis for the Washington Post.
"Man, they must really hate millennials and avocados in Australia."
Only Fortune seemed to twig onto the fact that Mr Gurner was merely using references to food as metaphors to describe millennial spending habits.
"The Australian real estate millionaire who suggested millennials need to stop spending so freely on avocados to buy a house might actually have a point," wrote reporter Lucinda Shen.
"According to a Bank of America Merrill Edge study published Friday, today's 18- to 34-year-olds are much more likely to prioritise travel, dining, and their gym membership over their financial future."