Yes christian brought their diseases that infested the native population, smallpox and syphilis also known as the christian disease How Europeans brought sickness to the New World http://www.sciencemag.org/news/2015/06/how-europeans-brought-sickness-new-world
White christian savages now telling others to go home Native Americans and Christianity have a history that dates to the the arrival of the first European explorers. This history is marked by genocide, cultural destruction, domination and resistance. Much of the destruction was done for land, politics, and power, but a significant part of it was done for religious reasons, as Christians embarked on a world-wide, conversion-by-the-sword "re-education" scheme. http://rationalwiki.org/wiki/Native_Americans_and_Christianity
Do you realize that there are now more Mexican immigrants just within the county of Los Angeles than there were Native Americans living in what is now the entire area of the United States and Canada? In terms of numbers, you can't even begin to compare present day immigration numbers with the peoples that inhabited North America before Columbus came. While I see the principle of the thing, the numbers we are talking about are just not comparable.
So no native tribe wiped out or displaced another native tribe in North America before Europeans arrived? Or is it only bad when Europeans do it?
The Mexican-American War along with the Treaty of GUADALUPE HIDALGO settled the issue of whose land this is.