How is slaughtering innocent bystanders of a conflict they were not even a part of prove your leaders to be "smart and strong"?

As I conquered previous Mongol land, I found remnants of burnt towns, skulls of the dead, and decomposing bodies of fallen soldiers who did not deserve the fate and brutality that they were met with while fighting Khan and his soldiers.

The great city of Baghdad was burned, in which I planned to conquer.

As Alauddin Khalji, a rival competitor for land, he viewed the Mongols as uncivilized by not showing any mercy towards their enemies.

Mongols also allowed for the advancement of women's rights, allowing them to divorce, remarry, fight in the army, own land and property, and participate in other activities that women couldn't do in other nations.

Mongols were able to create an empire with religious tolerance, which was very rare to see during this time.

Mongols used advanced military techniques that were never before seen by their enemies, including psychological warfare, which the Mongols mastered. For example, they would send a small force to bait the enemy into their retreat, and when the enemy was far enough behind the front of the battle, the Mongols would swoop in from behind and annihilate their opponent.

As Mongols began to expand, they began to spread the bubonic plague, both inadvertently and on purpose, which decimated the European population and destroyed their ways of life.

Burned the city of Baghdad to the ground, which was a large cultural hub and education center, and they didn't even bother to save the important documents and papers.

Mongols slaughtered civilians for choices their leaders made (people paid the price for the leader's arrogance)