Why Was It Necessary To Remove The Indians From The South?

In short, it wasn't necessary at all.
From my understanding it more or less went like this.
A: "This place sucks, let's move over there."
B: "Okay, but there are already people there."
A: "Who cares, they're indians. Let's just tell them it's our destiny to invade their land and drive them out of their homes."
B: "Great plan!"
A: "Hello there savages, move over."
Indian: "What?"
B: "It's our destiny and all that."
Indian: "What if we don't?"
A: "We'll kill you."
Indian: "What."
A: "But hey, you can have some of that land over there, we don't want it."
Indian: "Gee, thanks."