Armstrong has been stripped of his seven Tour de France titles and banned for life after an avalanche of evidence pointed to his involvement in a sophisticated doping programme.
The American has always denied he took performance-enhancing drugs but the International Cycling Union's (UCI) decision to ban him has left his remaining supporters out on a limb.
UCI president Pat McQuaid told gathered media earlier this week: "Lance Armstrong deserves to be forgotten."
That is the last thing we should do, according to Henderson.
"We've been told to forget about Armstrong," he told the Otago Daily Times from Melbourne yesterday.
"But you can't forget about Lance Armstrong in the sport because he is actually a reminder of how not to do it."
Armstrong's story of cancer survivor to seven-time Tour de France champion touched millions, and few wanted to believe their hero had lied and cheated his way to the top.
Imagine discovering Sir Edmund Hillary had only gone halfway up Mt Everest, returned and lied about reaching the summit. You would not believe that without extraordinary proof.
And that is how Armstrong was able to dupe so many for so long. There was no real proof other than the testimony of a disgruntled minority, he maintained.
The consensus now is that Armstrong was the ringleader in a grand conspiracy and bullied anyone who challenged the accepted narrative.
"I've never looked at Armstrong as a superstar and I don't think a lot of athletes have looked at him that way or would call him a role model," Henderson said.
"He lived a massive lie. He knew he was doing that for 10 years and didn't think about the future of the sport.
"I wouldn't say he is a knight in shining armour because he has the Livestrong Foundation, either. People have worked out what he is about, but the underlying fact is the money that has been raised for cancer and for Livestrong is quite phenomenal."
Armstrong founded the organisation in 1997 to empower and inspire cancer survivors and their families but stepped down as chairman earlier this month.
No question, Armstrong has been a beacon of hope for people during some dark times in their lives, but it was based on a false premise.
As for what will become of the seven Tour de France titles Armstrong won from 1999 to 2005, Henderson said that was up to the officials to decide.
In some ways, leaving the title blank will allow people to insert Armstrong's name by default.
But Henderson said drugs were "rife" during that era and it would be difficult to name a champion who had not been tainted by controversy.
Some wonder if cycling's reputation can fully recover following revelations its greatest champion was a fraud.
Sponsors have been keen to distance themselves from Armstrong and the sport, but Henderson believes cycling will survive despite the setback.
"The sport is heading in such a different direction now than it was 10 years ago and the future looks bright as far as I'm concerned. The guys coming through now are basically competing in a different sport.
"It is a beautiful sport. I can't even explain how big cycling is in Europe. The public love the grand tours.
"I've never ridden anything as crazy as the Tour de France, and I've never seen so many people in my life."
