It's a really fascinating topic, there's lots of arguments both sides, Some points I like: - A very advanced lifeform may view us the way that we view plants,

It's a really fascinating topic, there's lots of arguments both sides, Some points I like: - A very advanced lifeform may view us the way that we view plants, so basic that wiping them out for convenience sake is not even something that enters the realm of our ethics - we just do it. I imagine aliens coming to Earth and seeing us humans on it eliciting a response like one of us opening a container in the fridge and going "Eww mould" (ewww Primates) and then washing it all clear with hot water. - One would think that extra-species aggression would be a trait favorably selected by Darwinian evolution, so super-hostile aliens would survive and propagate. Hopefully that's negated by a post-scarcity advanced alien economy? - In the universe sentience is relatively rare, so finding another race is something that should be treasured, cherished and nurtured. - Maybe they'll see us as pets, and shower us with gifts What other scenarios can you think of? I especially like thinking about what happens when there's large intellectual differentials ...