These scientists are taking a highly anthropocentric perspective on a topic that requires a much broader treatment. Alien civilizations may have flourished and be flourishing elsewhere, but their electromagnetic signature may not have reached us, or maybe did millions of years ago. Or, they flourished in different ways. From our limited but growing knowledge, the chemistry on which life is based is abundant, so it’s inevitable. Meanwhile, we need to focus on preserving the life do know about. They’re absolutely right about that.