There is something strange about it, but there could be a number of reasons/answers.
Perhaps the Swedish media was hanging on to the interview in order to use it at the most opportune time. If they got wind of the rumour about the excommunications being lifted, doubtless they wanted to use the "scandal" to prevent the decree, or, failing that, to harm the image of the Pope.
Don't forget that the decree comes after over a million Rosaries were offered up for that intention. First we prayed for the Moto Proprio, then we prayed for the lifting of the excommunications. Both were granted. Just as it is clear that the decree is a direct result of Our Lady's grace, so it would be equally fitting were the powers of darkness to try everything to cause trouble for the Society and the Holy Father. The devil is doubtless trying to "get at" the Society in any way he can.
Also, the decree was signed in spite of "threats" from the ADL. This made the act an even braver one, given that the Holy Father must have known the response his actions would provoke in the media. Perhaps he will have to suffer much for his decision. Perhaps Bishop Williamson will, too.
At any rate, it is definitely a case of the "battle lines being drawn". Bishop Fellay says this:
Dear faithful, the Church is in the hands of her Mother, the Most Blessed Virgin Mary. In Her we place our confidence. We have asked from her the freedom of the Mass of all time everywhere and for all. We have asked from her the withdrawal of the decree of excommunications. In our prayers, we now ask from her the necessary doctrinal clarifications which confused souls so much need.
Now we pray for the doctrinal clarifications. Bit by bit, Our Lady's Immaculate Heart will triumph.