Well, if you want to be historically accurate, the people of Jmaestown were granted permission to live on the land, and in return, threw multiple feasts for the Natives. When the population got too high, the Native Americans would come in and slaughter men, women, and children so the settlers wouldn't encroach too far.

As a reaction, the settlers fought back and caused other settlements with peaceful natives to revolt, forcing European armies to come in and put down the natives, which ultimately caused tensions and littered America with battlefields and growing hostilities between the groups which ultimately lead to Custer's Last Stand, the Trail of Tears, and modern day reservations.

Also, the smallpox thing wasn't a planed attack as so many people falsely believed, Lois Pasteur didn't create germ theory until the late 19th century, people back then believed in miasma theory, which meant that disease was transferred through bad smells. The fact that Natives had never been exposed to smallpox and had no immunity passed along the generations meant that they were more susceptible to it. Despite what the retarded mainstream line of thought tells you, the settlers and Natives actually willfully helped each other most of the time, the Natives taught Europeans how to plant crops and the Europeans gave the Natives technology. It wasn't just a giant hatefest all the time, and the settlers didn't just take from the Natives and refuse to give anything. The Jamestown and all subsequent incidents were few and far between, but still enough to cause major hostilities .

But, if you wanna put sole blame on America, that's ok too.