It is quite simple. They truly hate humanity and believe that species bordering on extinction are valid and more worthy of existence then the average human.

The reality is that over the course of the history of earth, many species have come and gone, naturally, without any human intervention.

We, humans, have a chance to change and set the future of the entire universe. We alone are capable of terraforming other planets and even creating gigantic space-faring craft capable of exploring the galaxy and introducing humanity to other possibly habitable planets.

It's not that we shouldn't do it. It's that we HAVE to do it. And what will be the consequence if we don't? Nothing. All of those potentially habitable or resource rich planets (including earth) will simply end up being obliterated by the supernovae explosion of some nearby star.