Hansen was quizzed the day after his side's 52-11 victory over the French at Eden Park, with his assistant Ian Foster also commenting at length during the week on the tackle on Grosso by Sam Cane and Ofa Tu'ungafasi, which left the No11 with a fractured skull, but it is an issue that won't go away.
It took World Rugby four days to announce that Tu'ungafasi had been cautioned and two days out from the second test in Wellington, Hansen was initially reluctant to re-visit the incident. But in the end he compared it to a motorist doing everything right behind the wheel but who is faced with an unpredictable act from someone who runs on to the road.
"I think there's been enough said about that – as you've said, there's been enough debate," Hansen said. "You've got my opinion on it, it's on the record. The game is fluid, there are going to be times when people do get injured.
"Someone gave me a good analogy this morning, actually. Sometimes when you're driving your car and you're driving at the speed limit and then a little kid runs out in front of you – is that the kid's fault or your fault?
"In our game things are fluid and change and you can't stop something you've committed to and someone's angle changes. We have to accept there are going to be some head knocks. In saying that, we've got a duty to make sure we don't do the dumb ones – get them out of our game."
Neither Cane's high tackle (for which he was penalised), nor Tu'ungafasi's connection with Grosso's head, was found to have reached the red card threshold by either the television match official or the citing commissioner. Tu'ungafasi was given a formal warning by commissioner Freek Burger, from South Africa, immediately after the test, one that, interestingly was announced to the media only yesterday.
Asked if he was surprised by the late announcement, Hansen said of Dublin-based World Rugby: "No, not surprised. It takes a wee while for things to get over there – it's a long way away."
For Cane, who caught Grosso high due to the Frenchman's unexpected movement, not a lot changes. The All Blacks openside flanker insisted that the best tackling technique was always to hit lower than the ball and that's what he and his teammates always attempted to do.
"Ultimately we've got a big focus on tackling low because if you nail someone low you pretty much drop them where you hit them and that's what rugby's all about – winning the gain line," Cane said. "When you tackle high you get carried one or two metres so we're always focused on tackling low. If one guy goes low the other guy will try to wrap up the ball.
"But at speed things happen – I suppose with the explosiveness of the athletes things can go wrong. But I can pretty much guarantee that it's never anyone's intent to cause serious damage.
"Literally we're talking split seconds sometimes. It's easier when you look at it on the computer or slow the camera down, 'look, he could have done that', but when you put it back to full speed we're talking 'bang'.
"We spend a lot of time working on technique so hopefully the majority of the time we get it right."
Asked about the tackles that do go wrong, he said: "When something like that happens all we can do is trust the systems that are in place. They go to the TMO, if there's no issue there, there's the citing commissioner – he's got a job – and if there's nothing there then let's leave it there."
Cane isn't expected a revenge mission from the French at Westpac Stadium but nor would he be particularly worried if he did come in for extra attention.
"I think they will look to improve on their performance," he said. "I would be surprised if they were fuelled by something like that. I don't think we would as a team ourselves."
"No, to be honest I hadn't thought about it… but I don't mind anyway."