When the haters have a hunger to hate, the last thing thing they need is sustenance to fuel the righteous indignation. They have it, though - all the ammunition they need to pillory McCaw at this World Cup as rugby's version of Stalin.
It is, alongside the previously shocking treatment of the Pacific Island sides, rugby's greatest shame that McCaw is the subject of derision outside of New Zealand.
He is the game's elder statesman, the longest serving ambassador test football has ever known and a man laden with achievement. He is a player whose standing should be celebrated and respected by a sport that prides itself on inclusion and fraternity.
And yet the one man who should be the beneficiary of endless adulation is rewarded only in jeers and taunts.
If a by-product or secondary aim of this tournament was to turn the global audience into McCaw admirers, that mission may already be doomed.
A solitary "dumb" act doesn't change a thing on one side of the debate. But on the other it confirms everything and McCaw knew it the instant his foot had shot out.
"I was sitting in the sinbin at the time so I didn't have much of a comeback after that... [it was] a dumb mistake I made," he said.
"I knew straight away that it was a reflex thing and it wasn't the right thing to do. It put the team under pressure which you can't afford to do. It was one of those things that as soon as it happens you wish it hadn't [done it]."
McCaw's improved ranking as rugby's most disliked figure is hardly going to be catastrophic to the All Blacks' ambition at this tournament, but they would rather have liked the mood to thaw in regard to their captain.
Whether McCaw is genuinely bothered by his public enemy status or not is hard to tell. He says he's not, that he expects it and has become used to it. He gives the impression he's happy to buy coach Steve Hansen's argument that the animosity is a sign of respect. But humans want to be liked and it's ridiculous to believe anyone would enjoy being the subject of ire the way he is.
Still, the strength of McCaw is that he can endure just about anything - millions of cheap shots, a broken foot and now the ill feeling of millions of rugby followers.
He may well be a dead duck in the PR war but what will actually irk about his crass, stupid and entirely deserved yellow card is that it compromised the team.
He put his team under pressure and let them down. That's the bit he's mad about.