Many Americans perceived "Manifest Destiny" as benevolent, but why was it really an aggressive imperialistic move pursued at the expense of others?

Manifest destiny was a concept that was devoid of any consideration for the lives, land and property of the people against which it was targeted. With time it came to acquire a most imperialistic bearing by embracing the proud and selfish reasoning that because America had been made great by its Anglo - Saxon heritage, this made America supremely fit and suited to extend its influence beyond its continental boundaries, that now it was the nation's manifest destiny to achieve this. Nowhere are the interests of other people mentioned.