Again, I'm sure I can find clips of all astronauts also saying they believe life is abundant across the universe. The perspective you are talking about is a thing that happens to astronauts. It's true, space is very harsh and the planet has a fragile ecosystem and all that.
This isn't speaking to the idea that there are not millions of other planets similar to Earth? This is a perspective about how everyone on Earth is one species and we should take care of the planet and so on.
It does not mean Earth is the only life in the universe. Not at all.
Leroy Chiao, NASA astronaut and ISS commander, "I believe there is a LOT of life out there (in the universe)...it would be the height of arrogance to think we are the only life"
Dyane Carey, NASA shuttle astronaut - "when you do the math you can say there are millions and millions of planets that can support life in the universe..."