And I'm sure there were popes of the same time period who did the same thing - the crucial difference being that Christians of today don't treat medieval popes as ultimate examples of humankind; Muslims treat Muhammad as the ultimate example, to be copied.
Also, that was the middle ages, also knows as the dark ages.
What people did was done because they wanted power and control. Not because the bible really taught all that, they got away with it because they lied about what was in it. The reformation was giving access to it to the people by printing it in their own language.
Islam is still in the middle ages, it's books and doctrines are a blueprint to perpetuate it and the comparison to Christianity or practically any other religion is simply made to try and deceive.
But even if the comparison was fair. So what? Then Christianity changed hundreds of years ago ... Islam hasn't changed in a millennium - is that supposed to somehow excuse it or make it better? How does pointing to another murderer or rapist excuse the one you already caught, especially if they died 500 years ago?