I like to think they've been observing our civilization for a long time, perhaps even being responsible for our evolution, watching us like bacteria in a petri dish to see how we grow and change on our own. Our technology has reached a point where our military often catches a glimpse of their craft operating over our oceans and in space so they initiated communications with the established powers to point out that as soon as their existence becomes common knowledge the experiment ends and we all get to abandon this capitalist shit hole and become citizens of the galactic fully automated gay space commune.