Answer:
When the Europeans came they had aslo brpught many different diseases with them and sence the native Americans had never been introduced to these diseases it hit them fast and hard, it killed faster than you could imagine because people lived together, they cleaned themselves in the same place as other, and they all helped to gather food for everyone, they did everything as a group only causing more and more people to get sick. No Spanish man with a gun could ever do this damage because the disease was basically causing the natives to kill them self's without even realizing it.
I hope this helps and is what you were looking for :P