I mean they invaded Tibet and conquered it. That was "aggression." You can also interpret it as putting down an internal rebellion, but regardless deploying troops to a territory that you currently do not control and using force/violence to wrestle back control is "aggressive." Note that doesn't imply negative or positive connotations, "aggressive" is a neutral term. Again, I want to reemphasize the idea that I think this "aggression" was an unequivocally good thing.