Hello, half-baked space person here.

Of all the speculative answers on why another civilization would contact us:

What made this optimism nevertheless terrifying was the unknown of what the adults of the cosmos would be like. Would they be peaceful? Would they be so advanced that they would treat us as we treat a fruit fly or a rat, or a lab mouse, or even Laika the space dog? Would they treat us as food, the way we treat cows and pigs? Would they carry with them genocidal new diseases the way Europeans did to the Americas? Would they be the disease? Would they demolish the Earth to make way for a hyperspace bypass?

The flip side is our own (to extend the metaphor) child-like curiosity of the cosmos around us. Are we truly alone? What could we learn from other life (technologically, biologically)? Where are they at in their civilization's development? Is there evidence/ hope for us to come to a place of global unity or overcome existential troubles like climate change without great loss [actually the first link covers this too]?

Edit:

So both points I meant to link were from the same conversation. The link above would start at what I sought to answer. The start of Sagan's dialogue with Carson on the search for terrestrial life on that date:

It touches most of the conversations and some jokes along this thread. Worth a fun, informative listen.