McLaren announced its withdrawal from the Melbourne race late on Thursday evening after a team member was tested positive for the coronavirus.
The other nine team bosses met with Ross Brawn later in the evening, and Alfa Romeo was one of the teams that push for a cancellation, joining Ferrari, Mercedes and Renault in sending letters to the FIA explaining their rationale.
“As a racer it’s difficult to take this kind of decision,” Vasseur told Motorsport.com.
“But firstly we have to think about our employees, the safety of the fans, the image of the sport, the image of the sponsors, and also about McLaren, because it would have been a bit unfair to have let them withdraw alone. I think it was the right decision.
“It’s not easy for the team, because everybody pushed like hell to be on time in Melbourne, on the race team but also back in the factory.
"But we have to take the decision, perhaps it’s a shame that it’s a bit too late. But it exploded so quickly.”
The Bahrain and Vietnamese Grands Prix have been officially postponed along with Australia, and most expect the season to start no sooner than the Azerbaijan Grand Prix in June.
“The situation is not easy, it’s a huge disaster all over the world," Vasseur continued. "F1 is not the centre of the world, so let’s do it step-by-step. The first step is not an easy one.”