If we are serious about researching or preserving alien life in our solar system, we would have to be very cautious with what we do. But most likely, economic forces will start to dominate our actions in space, as they have always done on Earth.
Perhaps most advanced intelligence comes in the form of distributed hive minds, and something like a "civilization" is regarded by most sentients as something akin to a pack of wolves or an uncontrolled mob? Maybe we're the ultimate ethical dilemma: All of the bad qualities of a cancer, but you can't ethically kill us because every one of our units is an independent sentience.
Our neighbors are quietly watching us, hoping we'll choke in our own industrial effluents and kill ourselves off in the resulting ecological chaos, so no one has to taint themselves with the unpleasant task of sterilizing our system.
Manufacturing spacecraft capable of traveling between the stars in any reasonable amount of time, if possible at all, would be an immense industrial undertaking, the pinnacle of not just scientific knowledge but societal complexity in order to coordinate the resources involved. Any alien race capable of doing these things must have also committed the sins that they're smugly damning us for, and to a far greater degree than we have.
Starship Troopers.
This only happens because a human being's short lifespan, limited mind, and constricted point of view mans that a human's perceived self-interest is very limited in scope. A planetary scale hive mind could have a much longer lifespan and a (literally) inherently more global view.
Externalities arise because of a limited scope of knowledge, and persist because of self-interests of tiny scope. We think markets are so wonderful, because the distributed computational power of many individuals can keep up with global complexity. What if a single hive mind could command the same number of neurons, without the disparate competing self interests getting in the way?
Note that my comment specifically mentioned hive minds. A civilization has many cooperating/competing individuals. Most of civilization's problems are epiphenomena arising from this fact. What if most galactic factions aren't composed of many individuals, but are effectively one distributed mind? What if they regard our social pathologies as pestilential?
Without giving away too much... there is some tension between scientists trying to use domes and gear to prevent contamination vs. colonists and miners.