Explaining the Government's mistake, Attorney-General Christian Porter blamed his own office, saying his staff interpreted Hanson's motion as "opposing racism" and "the associations of the language were not picked up".
They can't have looked very hard.
If you are wondering what the big deal is — it is, after all, perfectly OK to be white — you are missing one crucial thing. Context.
The phrase has a sinister history.
"It's OK to be white" was first dreamt up on 4chan's "politically incorrect" image board, which is a sort of gathering place for anonymous trolls.
It's a diverse group, in its own weird and disturbing way — you will struggle to find a more comprehensive cross-section of the internet's sewer dwellers anywhere.
There are white nationalists, men's rights agitators, some of Donald Trump's more demented fans, people who just really hate political correctness and some straight up racists and misogynists.
You are welcome to take a look at the forum yourself — thanks to the wonders of modern technology, it is just a simple Google search away — but expect to come across some pretty nasty stuff.
So, how exactly did the "It's OK to be white" start?
It was spawned when an American university, Boston College, tore down a pair of provocative signs in October last year, saying they were "offensive".
The posters bore an image of Uncle Sam, with the caption: "I want you to love who you are. Don't apologise for being white."
"An outside group, well known for such tactics, posted offensive materials to provoke controversy. We stand united in opposition to their actions and denounce all forms of hatred," the college said at the time.
The 4chan trolls reacted by refining the sign's message and distributing new posters at other universities across the country as a Halloween stunt. Here is the original post laying out their "game plan".
It called for people to dress up in Halloween costumes (so they could stay anonymous) and plaster the signs on campuses, in the expectation the media would go "completely berserk".
"Normies tune in to see what's going on, see the posters saying 'It's OK to be white,' and the media and leftists frothing at the mouth," the plan read.
"Normies realise that lefties and journos hate white people, so they turn on them. Credibility of far left campuses and media gets nuked, massive victory for the right in the culture war, many more /ourguys/ spawned overnight."
It didn't happen quite so dramatically, but signs bearing the slogan did start to pop up at schools and universities in the US and Canada. For a while, that was pretty much the end of it.
Then, a month later, Lucian Wintrich, the White House correspondent for a right-wing, conspiracy theory peddling website called Gateway Pundit, tried to deliver a speech at the University of Connecticut entitled "It's OK to be white".
About 100 people attended the event, many who interrupted Wintrich, booing and chanting "Go home Nazi!"
And there were ugly altercations. Wintrich grabbed one of the protesters after she stole a piece of paper off his lectern, and students vandalised the venue. The police were brought in.
"We live in a tense and angry time of deep political division. Our hope as educators is that creative leadership and intellectual energy can be an antidote to that sickness, especially on university campuses," the university's president said.
"Between the offensive remarks by the speaker, who also appeared to aggressively grab an audience member, and the reckless vandalism that followed, that was certainly not the case on our campus tonight."
Australia was properly introduced to the "It's OK to be white" slogan when Canadian alt-right activist Lauren Southern visited the country for a speaking tour in July.
Southern donned a T-shirt bearing the catchphrase as she touched down in Brisbane.
"It's a pleasure to land here and see Australia upholding its commitment to free speech and Western culture — something that may not be here for much longer if left-wing Australian politicians continue their pathological worship of multiculturalism," she said.
So, there's the background. "It's OK to be white" is a well-known slogan concocted by an internet forum crawling with white supremacists, which has since been adopted by the trollier elements of the far-right.
Speaking in the Senate today, Labor's Penny Wong ridiculed the idea that the Government misinterpreted Hanson's motion.
"There is nothing innocent, nothing unknown, nothing hidden about this phrase. Frankly, the claim that somehow the Government didn't understand it or didn't know about it is not believable," she said.
"We are supposed to believe that no one in the Government paid attention and some junior staffer ticked it off, and then Government senators just filed in and sat behind Senator Hanson oblivious to the fact that they were endorsing a racist motion designed to promote Nazis, the Klan and other white supremacist groups."
Hanson, for her part, has angrily denied any suggestions her motion was racist.
"If I had said it's OK to be black, every single senator in the chamber would have voted for it," the One Nation leader said today.
"As I stated on the floor of the Senate, I have always believed it is OK to be black, white or brindle."
One of those who opposed the bill, Justice Party Senator Derryn Hinch, called it a "headline-grabbing stunt".
He said Hanson was "in a race" with another of her colleagues "to the bottom of the sewer" by seeing "who can be the biggest, the loudest, racist bigot".
