(Taking a step back, big picture, so forgive the mystical language... We ARE talking about morality here, after all...)
What if the ONLY reason humans are worth it to Gaia/life/Earth/etc is the ability to seed life on other planets? What if we're Gaia's reproductive system, the whole reason Gaia puts up with our massive extinction-causing existence?
I've definitely had this thought before. Humans are like a long shot bet. It comes at the cost of the risk of a major extinction event but, if successful, could seed life across worlds directly.
Imagine a hundred worlds all with life forms subject to evolution.
Basically two ways of that life growing past its planet:
1) A lucky asteroid strike or other outside event
2) A form of creature that can build tools to get out of the planet
Only #2 would have an inbuilt strategy for galactic survival.
What if the ONLY reason humans are worth it to Gaia/life/Earth/etc is the ability to seed life on other planets? What if we're Gaia's reproductive system, the whole reason Gaia puts up with our massive extinction-causing existence?