Cheating, plain and simple. More proof, if it was needed, that football needs far better on-field policing.
"Something has got to be done," says Graham Barber, a former Premier League and FIFA referee with hands-on experience of dealing with Henry.
The answer is not video replays. Video could have helped in Paris on Wednesday night, because replays clearly showed France's captain steering the ball with his left forearm and hand onto his right foot for the pass that William Gallas then headed in.
But video isn't always clear-cut. More importantly, stopping every few minutes to consult replays would ruin the flow of the game.
Football isn't tennis. Technology works in that sport because play has already stopped when players use the high-tech Hawkeye system to challenge linesmen's calls.
But in football, play often continues after shirt-pulling, dives, handballs and other fouls that could, in theory, be spotted on video when missed by referees. That actions flow one after another, end to end, is part of football's magic.
Stop-start, stop-start shouts from referees of "Hang on a second, let's pause and take a few seconds to look at that on television" would be a disaster. Might as well toss in commercial breaks while we're at it, too.
Barber says frequent referrals to video would be like "pulling the emergency chain on the train if someone spilled a cup of coffee."
"I don't think video cameras will work because it won't work for the game," he says.
But adding more officials now makes more sense than ever.
Henry most likely would have been caught red-handed had the two extra assistant referees being experimented with this season in European club football been employed for this World Cup play-off.
The additional pairs of eyes in UEFA's Europa League specifically watch the goal area. Radios link the assistants to the referee.
The Swedish fireman who officiated at Stade de France, Martin Hansson, was 20 yards away when Henry used his hand, too far to see. The view of Hansson's assistant on the touchline also was seemingly obscured by Gallas as he rushed in to head the goal. Until that horrible mistake, Hansson had had an excellent match, seemingly unfazed by the 79,000-strong crowd.
But an extra official alongside the goal, like in the Europa League, could have been perfectly placed to disallow Gallas' vital score that broke Irish hearts.
"Whatever happens people will make mistakes. If you have 10 officials around the field, people will still make mistakes," says Barber. "But the more eyes you can have on it, the better."
The players themselves also could be doing far more to keep play fair.
Rather than immediately tell the referee that he had broken the rules of the game, Henry charged off in celebration behind Irish 'keeper Shay Given's goal, spreading his arms wide with joy. After the match re-started, chants of "Cheat! Cheat! Cheat!" rang out from the thousands of Irish fans when Henry next touched the ball.
Belatedly, after the match, France's record goal scorer confessed that he'd handled. He said the ball "bounced" onto his hand, although it looked intentional.
As if to excuse his actions, the Barcelona forward recalled that he had been on the receiving end of a similar injustice when he played his club football for Arsenal in England.
Henry seemed amused when a reporter asked him if he'd considered saying something straight away to the referee.
"I stop, speak to him and then pass (to Gallas)? You're funny," he said.
Barber recalls yellow-carding Henry for a dive in the 2003 FA Cup final and says the player acknowledged afterward that the caution was deserved.
"I do think that Thierry Henry is an honorable man," he says.
But the sad truth is that many players, like Henry, also do whatever they can to get away with fouls and unjust decisions. Ireland defender Sean St. Ledger acknowledged as much, in speaking about Henry's handball.
"If it had been one of our team we'd have probably done the same," the Times of London quoted him as saying.
So bring on more officials, or the cheats will continue to prosper.