This is a pretty cool article about a subject I most certainly have an opinion on. My idea about this is simple. If alien life can grow to the point that they are traveling among the stars, they have probably gotten to a point where they’ve killed themselves off. I don’t believe we’ll ever see interstellar life that isn’t in fossilized form. By the time we can travel the stars (assuming we haven’t killed ourselves by then) alien civilizations have probably risen and fallen. Use Star Wars as an example. The story takes place a long time ago in a galaxy far far away. I’ll add, and then they all died.
This article isn’t quite as grim as that.
As Berezin explains, this doesn’t necessarily mean a highly developed extra-terrestrial civilisation would consciously wipe out other lifeforms – but perhaps “they simply won’t notice, the same way a construction crew demolishes an anthill to build real estate because they lack incentive to protect it”.ScienceAlert