It's true that Indians warred with Indians as did every group of people against their neighbors.. But, a superior army? That, my friend, is where you lack knowledge about historical fact.
1)The main killer of Indians was DISEASE. In fact, most historians estimate it as most likely the killer of 90% of the people-in the first few years of contact! You see, Indians at that time, unlike the whites, had this habit, called bathing every day. Because of this and the plagues that Europe had experienced, the whites had defenses against these diseases that they were crawling with and that the Indians had never come across.
2)If you study the TECHNIQUE of the Euro-American army at that time, it is laughable. They would line up in a row, shoot, and then reload. Guerrilla warfare, hiding in the bushes, etc, is what they learned here. So, the superior technology of guns and superior technology of native war techniques really ended up in a wash.
There is much more I can get into as a response to your argument-such as, even though disease wiped out so many and even though whites had guns and even though whites lied, cheated and stole-they still weren't able to complete the genocide. Eventually, the US government saw that their efforts were futile and decided to give up and try cultural genocide instead!
My point is to fully research a topic from many different points of view rather than just accept that one culture must clearly be superior to another in order to wrap genocide up in a neat little package.