Would we colonize a planet already inhabited?

[DaveStrider]

If we're talking about colonizing planets it's safe to assume FTL travel (otherwise it's probably not going to happen ever). FTL travel, while convenient, is an extremely deadly weapon, so i find it highly unlikely that we'd let countries like north Korea use it (assuming that the west get the technology first) when they could simply make the ship face earth and demand surrender. Call me an optimist, but based on that fact, i'm happy to assume that the people in charge of colonization will be democratically elected, and by extension, care about public opinion. If we were to eliminate a (sentient) species just so we could colonize a planet there would be a catastrophic outcry, and that leader will never be elected again. So, i believe that assuming: a) FTL travel is possible, the people in charge of colonization are democratically elected, colonization would be prioritized by political ramifications as well as profit, meaning that Earth-like planets with unintelligent wildlife (probably means ape level) are the best possible for colonization.

The only thing we get out of colonization is a population growth. Planet-side industry would only really be used to sustain the colony (given the prohibitive cost of launching through an atmosphere), and since our asteroid belt is more than enough to sustain our industry for a long time, trade is practically useless. Really, there isn't much profit in colony building that i can see (other than the fact that humanity isn't doomed if earth is invaded), So i doubt that we'd invade an inhabited planet just for a little more breathing room.