It is not just the Qur'an, corthos. The problem is also Muhammad himself.
Muslims have always tried to follow their role model - Muhammad.
Muhammad and the Qur'an have taught his followers not to steal, and yet during 623-624 he began series of raids upon merchant caravans. Merchant caravans were traders, not an army of soldiers, so Muhammad and his followers were nothing more than highway bandits or pirates, looting and selling people as slaves.
And yet Muhammad rationalise and justify their actions as not stealing, by saying they were at war, so it is okay to kill, steal and sell war captives to slavery. Muslims now have loophole in the Qur'an, where there are justification for stealing, killing and slave trade.
Muslims often quote the Qur'an, and say not to start war, and only fight against enemies in self defence, but it is Muhammad himself who started the wars against Mecca, through his act of piracy, raiding Meccan trade caravans.
Raiding caravans are not self defence, because merchants are not soldiers.
Muhammad always try to justify his crime by hiding by his "prophethood" and behind his religion. So Muslims who commit crimes also tried to hide behind their religion. So if Muhammad can do these things, then it is okay to follow in his footsteps.