"When you are giving someone the death penalty, which they essentially did, you cannot tolerate shoddy work, which they clearly did," Armstrong said in a pointed criticism of the French lab that conducted Landis' positive testosterone test during the 2006 Grand Boucle.
A three-person arbitration panel decided against Landis in last month's ruling, which resulted in a two-year ban in addition to the loss of Landis' yellow jersey.
Landis cited the Chatenay-Malabry lab's mislabelling of his positive sample in his defence against the doping charges and the arbitrators consented that future errors from the lab could result in the panel overturning the Landis conviction.
Tour de France
Slipstream ready for Tour challenge
21/03/2008 AT 14:44
Armstrong, a seven-time Tour winner and former team-mate of Landis at US Postal, described the ruling as a negative one for athletes everywhere.
"I don't understand that type of rationale and I don't understand the verdict but it's tough for Floyd, it's tough for cycling," the 36-year-old American said.
"At the same time, I think it's also really tough and unfortunate for the fairness of all athletes. Because you never know when you're in that position, when an athlete's in that position, and you want to make sure that everything's done right."
Since Armstrong left the sport after winning his record seventh Tour de France in 2005 cycling has faced a series of doping scandals, including a catastrophic 2007 Tour that saw both yellow jersey Michael Rasmussen and pre-race favourite Alexandre Vinokourov booted from the race.
"The competitive side is definitely going through a tough period. But I think all of sport is going through a tough time," Armstrong said.
"You could look at cycling and say, 'Oh, they're all cheaters.' But you know what? You can look at the [NFL's] New England Patriots and say they're cheaters too."
"You could look at the McLaren Formula One team and say they're cheaters. It's top-level sport and there's a lot of money, a lot of pride, a lot of fame on the line. People are going to cut corners."
Championship leaders McLaren were forced to surrender the Constructor's title to arch-rivals Ferrari after spying charges, and Patriots coach Bill Belichick was fined $500,000 (£250,000) for using sideline cameras to spy on an opposing team.
"It's the job of the governing bodies and the police and all these agencies to make sure that what we're watching is pure and clean," Armstrong said.
Tour de France
Landis makes final stand
19/03/2008 AT 07:52
Tour de France
Valverde plans late peak of form
09/01/2008 AT 23:27