This kind of sacrilege at large Papal Masses has been happening for decades, with somewhat more caution under Pope Emeritus Benedict. Communion should not be available for all at those enormous venues.
Consider also how many hosts must have been consecrated for a crowd of 5-6 million! How were they consecrated (e.g. how do you get them all onto a corporal for the consecration, or does each priest come to the event with his cache of consecrated hosts in tow for the long and laborious journey to the stadium, with no due proper reverence)? Then, how do the priests get from the one papal altar out to where the millions are? It is physically impossible! What is most grievous of all is what happens with all of the hundreds of thousands of left over hosts and particles and vessels to be purified and priests fingers to be purified, not to mention the fingers and hands of all the handling crowds. Over the past few decades of papal events I have experienced the organized sacrilege at such events!
For example, I have a letter of gratitude from the Vatican for my participation with a brother priest at the Jubilee 2000 Corpus Christi Mass at Saint John Lateran (the Pope's Cathedral) at which His Holiness Pope Saint John Paul II presided. After communion distribution, at that Mass for a modest crowd of probably less than ten thousand, none of the priests distributing communion knew what to do with the ceramic communion bowls and cellophane which covered them, hosts and host particles which were all over everything. So we took the initiative to establish some order in the careful collection at a side chapel altar of all the bowls, etc. as they were shuffling hurriedly in, and the nun sacristan in turn took stacks of them to large tables in the sacristy for the purification. We two lone visiting pilgrim priests stayed and spontaneously purified everything and thereby missed the renowned Papal Corpus Christi Procession from the Lateran to Saint Mary Major. When we came out of the Lateran Basilica we knelt down before the large movie screen in the portico to receive the benediction with the Most Blessed Sacrament which at that moment the Holy Father was imparting from the other Basilica at the procession's end.