This is not true, please don't propagate stereotypes on a public forum even if it is an attempt to brag about Australian culture.
He's certainly playing up a character to a degree, but it's not too far off-base for a lot of folks I know who play up this kind of character when they're having a bit of fun anyway.
For the cooking show this guy's doing it's actually informative, gives good advice, and keeps it pretty easy to follow.
Very useful for folks who genuinely find it scary to cook anything that didn't come out of a packet or had more than four steps.
Although it's not too far removed from (the very non-Australian) Stephen Fry saying "Fuck off!" responding to a Derren Brown card trick at about 1:50. Both are impressed by something.