In the midst of a refereeing and VAR storm Pierluigi Collina was calm. A media briefing on refereeing mid-tournament is not a new occurrence. At the 2018 World Cup a similar conference was called. Except then it was easier. It was about success. The much-maligned VAR was, overall, working.

This time the attention is on the game’s rules and the implementation of those rules in a way few would have expected before a ball was kicked at the Women’s World Cup. But Collina, the chairman of Fifa’s refereeing committee, was on a mission. In a Marcelo Bielsa-esque session at the Parc des Princes, Collina talked through controversial rule by controversial rule with the aids of PowerPoint and video. Leaping up to test a member of the press on whether a photo on his phone showed a ball on the line – “No,” the bemused reporter replied – Collina swept across to bring a different angle into view and had his “ta‑da” magician moment.

Later, he interrupted a question, keen to show frame-by-frame an incident in Sweden’s defeat of Canada to show exactly why there was a lengthy stoppage and whether prioritising accuracy over time was correct.

Responding to the most common complaint, that the Women’s World Cup is being used as a guinea pig to test these new rules, he said these rules have already been used in the Under-20 World Cup in Poland and are being used in the current Africa Cup of Nations and Copa América. Last December all 24 nations competing at this World Cup were invited to a meeting on the rules, while teams were able to test and begin playing under the rules to practise during the two international windows of 2019. “On none of these occasions did we receive any complaints or questions,” Collina said. “They were accepted.”

The decision to suspend the booking of goalkeepers that breached the new rule of keeping a single foot, rather than both, on the line, was taken following experiences of the new system at the under-20s in Poland, Collina said. “We realised in Poland that all the incidents were not deliberate. It was because of a lack of control of the body. An honest encroachment. We thought it was harsh … It’s a temporary dispensation so will be discussed further.”

The response to the new one-foot rule surprised Collina. Because it was designed to help shot-stoppers. “Keeping two feet on the line is impossible”, he said.

“If the law that existed is not effective, or enforced by the referee, we have to change it. First we thought we have to change it to make the goalkeepers’ job easier. So we decided to allow them to step one foot off. This is the only change we made.”

Yet rather than the rule itself being the problem, it is the stringent implementation of it, to the millimetre, that is drawing ire. Not just for goalkeepers on the line but for offsides, too. VAR leaves no room for manoeuvre or subjectivity and Collina, the head of Fifa’s refereeing department, Massimo Busacca, and Fifa’s senior manager of refereeing, Kari Seitz, are convincing in their sympathetic picking apart of whether it needs to be so hair-splitting.

“Today, in matches with VAR, if the technology makes us able to view something we cannot ignore it,” Collina said. “It doesn’t matter if it is 2cm or 20cm, there isn’t a small offside and a big offside. If a ball is over the line by 0.5cm its a goal. There are not small goals or big goals. It’s not a matter of small encroachment or big encroachment, it’s just encroachment.”

Scotland’s Lee Alexander saves Argentina’s Florencia Bonsegundo penalty but the goalkeeper failed to keep both feet on the goal line and a retake was awarded. Photograph: Lucy Nicholson/Reuters

He was dismissive of Cameroon’s complaints over perceived England offside incidents during their hotly contested game in Valenciennes on this score: “They all have the right to complain as long as the complaints are based on facts. If they are not based on facts I have no time for them.”

However, “not all decisions are black or white,” the former referee said. “There is room for interpretation. I know there is this mood. And we ask ourselves what could have been done differently and it is hard to find the answer, especially when the referee took the correct decision, or when VAR made the correct decision. If my common sense damages someone else, I cannot use common sense.”

The Scotland goalkeeper Lee Alexander stepped off her line to save Florencia Bonsegundo’s penalty in the 93rd minute against Argentina forcing a retake. The resulting goal sent Scotland out of the tournament. Collina believes the state of the match meant the decision was more controversial, rather than being incorrect, and that had the incident taken place in different circumstances people would have given it less attention.

On handball incidents, though, he was more evasive, brushing over the decisions in the same “correct” or “incorrect” manner, ignoring the bigger questioning of the rule itself: that the arm must be in a “natural” position.

When reviewing the late penalty that handed the Netherlands a quarter-final spot against Japan he ran through the VAR process but did not take up the question of whether, given Saki Kumagai’s contorted straining body, her arm placement is “natural” in the context of her movement and whether, to be frank, having limbs is being penalised.