I was making a mental list the other day of all the things that creatures from another planet may find horrifying about us, as a race, and why they may not want to make any sort of contact. Assuming, of course, that there's some other form of life out there that can see what we're doing.
For one thing, they may be disgusted by the fact that the one thing we've found to kill bacteria – antibiotics – has been so overused that we're developing immunities to it as well as giving the bacteria time to adjust, mutate, and modify (since nothing new has been created in decades).
We pump these antibiotics and other hormones into the animals that we eat. Animals that we managed to trap and force to procreate so we can eat their young. Because we noticed that we kept eating all the other ones so much that they were disappearing from the planet.
Then we take their young and shove them in boxes so they can't move or get too muscular and tough, so they taste real good to us.
The creatures from outerspace notice, too, that we take some our food and cook it while it's still alive, or pluck it from the ocean while it's still very young (lobsters never stop growing and used to be found weighing 20-30 pounds and feet long, now we snap them up at 2 or 3 years old and just a couple of pounds). Then we take their only form of protection away from them – because they're very territorial and will fight – by snapping rubber bands onto their claws, along with a dozen or so others into a tank of dirty water where they await their death-by-dinner.
These aliens may find it horrifying that many of us keep some animals in our homes, dressing them up as people and treating them like babies (toting them around in handbags made from other animals that cost a fortune while our brothers and sisters starve, freeze, or heat stroke to death a few miles away). At the same time there are other people from the human race that abuse the same kind of animals that are treated as children by others.
Then we sit in front of a glowing box that shows us pictures of other humans shooting animals for sport while they jerk the lifeless heads around, admiring the fine antlers on a deer or the graceful body of a moose. Then they chop off its head and put it on their wall, calling it home decor.
Or what about the people who dangle sharp metal hooks in the water, teasing fish? Once they actually catch one, they hang it around in the air, brutally depriving it of its breath before yanking out the hook and tossing the fish back in the water, most likely to bleed to death.
They're mortified to watch as human beings kill and crush up the bones of other animals, drinking it with soup in the hopes of maintaining an erection — but not to procreate, just for pleasure.
For all our self-congratulatory talk about being the most intelligent species on the planet, we sure aren't very nice to the rest of the ones that share the earth with us.