Correct, they killed millions for no reason except for gaining more land which would just be taken away from them at some point.

Yes, but at what cost? Millions of people were murdered for them to be able to do this.

I agree, he went and killed millions of people just to gain more land and turn more people into Mongols.

They expanded trade as far to the west as possible and as far to the east as possible.

The fact that people were able to walk throughout the whole trade route with as much gold as they want and not get robbed because the tight security shows how they were civilized.

Many civilisations and cultures were combined to reduce warfare.

Marrying many women would mean there was not one true family for each husband and wife. Therefore, that is uncivilized.

Khan had harsh military tactics killing people for no reason.

They were uncivilized becuase they wiped out millions of people.