Picked a side? These aliens, if that's what they are, probably look at us the way we might look at monkeys. Whether one troop is tossing feces at another troop is really of little interest.
I always figured the arrival will take shape along the lines of the Europeans’ showing up on the shores of the new world.
Great puzzlement, caution and observation, hiding behind rocks and trees, then outreach and a couple nice dinners.
But somebody will steal something or shoot somebody...and the slaughter will begin.