...and were excommunicated for it (BTW, it was not mere sack and loot, but conquest of the Byzantine empire). Same for the crusaders who sacked Jerusalem during the First Crusade. So I do wonder what the pope was apologizing for, his predecessor already did what he could.
Are you also going to pound on Richard Lionheart who having defeated the Muslims in battle and then negotiated a peace treaty in which the Muslims promised not to mug Christian pilgrims on the road to Jerusalem? Will you pound on the Crusade that consisted of the German Emperor landing a huge force on the shortest road to Jerusalem and then engaging Saladin in some quick negotiation about safe passage for pilgrims and then leaving? And notice BTW that safe passage for pilgrims keeps coming up, think the Muslims should have gone unpunished for mugging them?
Are you going to pound on the Crusaders who stopped the Muslims from coming into Europe through Spain or the Church sanctioned war that saved Vienna? Or the battle of Lepanto? Or would you rather see Europe look like the Middle East? I will note the complete absence of atheists, Protestants, Lutherans and non-Catholics in general in stopping Muslim invasions (and I am Lutheran, ie non-Catholic).
Some of the Crusaders are worthy of condemnation, some should be praised, some were simply incompetent, some simply no better than anyone else of their time. A good number did us valuable historical service keeping Muslims out of Europe. Or do you actually believe the Western world would still be as it is now with Moslems ruling much of Europe?
During the Crusades? That's like saying "Where were the Wesleyans when Athanasius needed them?"