One top Swedish official accused the IOC of putting politics ahead of sport and jeopardising the future participation of National Hockey League players at the Olympics.
Sweden lost the final to defending champions Canada 3-0.
"They (the IOC) have given amateurism a face and it's sad that it will affect Nicklas and the hockey organisation," Swedish team manager Tommy Boustedt told a news conference.
"The timing with this was awful and my suspicion is that this is political. They got the decision two days ago. They waited until it would make a really good impact on you journalists."
Although the IOC has not confirmed that Backstrom failed a test, Swedish team officials pulled him from the game after being told that a test showed an elevated level of the stimulant pseudoephedrine.
Backstrom said the adverse finding had come from an over-the-counter medication he uses to treat a sinus condition.
He said he had been using the medication for years without any problems and told the drug testers he was taking it when they asked him for a sample after his team's quarter-final win over Slovenia on Wednesday.
"I've got absolutely nothing to hide," he told a news conference. "It was shocking to me and at the same time I'm here right now and I have to deal it.
"I haven't done anything differently in the past seven years and I've been playing internationally all that time.
"I was watching the game at the village. I was ready to play probably the biggest game of my career then two and a half hours before the game I get pulled aside."
Team doctor Bjoern Waldeback said the substance Backstrom had tested positive for was pseudoephedrine, a stimulant, contained in a pill he had been taking for many years.
"He has problems with sinusitis and allergic problems. He has for several years taken one pill a day of medication called Zyrtec-D. It contains psuedoephedrine," Waldeback said.
"Nicklas was tested several times before the Olympics. Nicklas also asked me before the Games if he could use this pill, and I told him he could take one.
"I feel a very big responsibility for this as I am medically responsible.
"But on the other hand, we could've never imagined the consequences of taking a medication that hardly affects the person and ruins the greatest day of his life."
The International Ice Hockey Federation (IIHF) and the NHL both weighed in to support Backstrom, saying he had done nothing wrong.
"We did have a circumstance in Vancouver (2010 Winter Olympics) where a player did have a level above the accepted level," said Mark Aubrey, the IIHF's chief medical officer.
"We certainly appealed to the IOC and the IOC was able to do another test on the player the next day, which did show that the level had come back to below the accepted level.
"I feel strongly as a medical person that there certainly is no doping in this instance. He is an innocent victim, and certainly we support them strongly. Doping is certainly not allowed, but this is not a case of doping."
The NHL released a statement saying they did not consider Backstrom had done anything wrong and as such, he would be allowed to resume playing for his Washington Capitals team when he returned to North America.
"Subject to confirmation of the facts as we understand them, and given the fact that the substance is neither prohibited in the NHL nor was used in an improper manner here, we do not anticipate there being any consequences relative to Nicklas' eligibility to participate in games for the Washington Capitals," the statement read.
Swedish team officials said that were angry at the IOC because of the timing, saying they were only told two hours before the game.
When the team sheet was originally listed for the final, Backstrom's name was still on it as Swedish team officials tried to get the ban overturned but time ran out.
"I didn't get a definite decision that he couldn't play until during the warm-up, so then we had to just take it from there," said Sweden coach Par Marts.
"It's like kindergarten. Canada is the best team in this tournament and I think we are second best. I think we should have the right conditions to compete with Canada and we didn't have that today."
Boustedt said the IOC's handling of the case had cost his team any chance of winning the gold medal.
"I talk for the players, I talk for the coaches and the whole staff, they're all very upset today. Our opinion is that IOC has destroyed one of the greatest hockey days in Swedish history," Boustedt said.
"That was one of the worst games we've ever seen, not because of outcomes and the way the team played, but because Nicklas couldn't compete in the game. This is one of the toughest days for me and Swedish hockey, and all because of IOC.
"This can further jeopardise participation of NHL players in Olympic Games because I know that both that NHL and NHLPA are incredibly upset about this, seeing this as an attack on their business too," he said.