So, if there are no other organic life forms out there, that would make humankind the most intelligent life force in the universe (as we destroy each other and our very own planet)? That doesn't wash. We are not alone.
That argument doesn't really make sense to me, but I agree we are not the only intelligent life in the universe. It's just that it's unlikely that we'll ever meet any other advanced civilizations because of the size of the universe. Unless, of course, there just happen to be civilizations nearby, but we've monitored the nearby areas and haven't found anything yet.
RANDOM THOUGHTS
As far as the planet goes, we just recently became advanced enough to actually impact the planet. We've noticed the impact and are working to address it. I suspect every advanced civilization in the universe probably goes through something similar. There's nothing evil about it, and it benefits nothing to say that we're literally destroying the planet via our evil ways. That's not happening. We aren't destroying it. We've changed the temperature an extremely small amount, but we didn't realize what we were doing.
The biggest thing we need to work on is population control, but when China tried it, the rest of the world called it a human rights violation, so it looks like we're not going in that direction. Without that, urban sprawl is a real problem that needs to be addressed. Birth rates in most developed countries are dropping, but it needs to be watched.
Back to the aliens, I disagree with people who think the aliens would come here but not make contact or come here to take us over. Based on our current knowledge of physics, coming here would be next to impossible from just about anywhere in the universe. So if they somehow did manage to make it here, I suspect they would want to talk instead of wasting their trip. They are very unlikely to want to drain cows of their blood and kidnap hillbilly's for anal exams. If they bother to come here, the only thing they can really want is knowledge, and the best way to get that is through communication. I guarantee that anyone advanced enough to get here won't be afraid of us. Anyway, in a universe this vast, there are no unique resources on our planet. If they wanted resources they could go somewhere with no advanced species where they won't be bothered while they take what they need. (And don't, please don't, start up with the alien fertility nonsense. They don't need us to make baby aliens. That's ridiculous.)
And there is zero reason to want to take us over. They don't need slaves. They don't need us at all. This sounds stupid, but it's true: Humans are only a decade or two away from making robots with advanced AI that will be superior to humans, so I don't expect that Aliens will be all that impressed with humans. Maybe they'll want our robots (just kidding, they'll have their own), but all we really have is human history. Our stories. I can't see them wanting anything more than that.
I just don't think that Aliens who can make it here can be evil. If humans were just slightly more evil, there wouldn't be any of us left, and I assume that applies to any species anywhere. Every civilization is going to reach a point where they have the ability to destroy themselves. If they don't, that's a very good sign.