The aliens didn't mess with the human race. They didn't do it any harm, they didn't change society's views, they didn't destroy cities or kill thousands. All they did was make a proposal that they move to earth, and only because their home planet was dying quickly. They were smart, really smart, and they assured the humans that they meant no harm. They've kept to themselves for years now, and have never once caused harm to humans (as a whole, or course. They get into fights sometimes, but no more often than the average human).

But the humans don't care about that. They don't care that the aliens have made numerous attempts to help them, giving them crucial knowledge for science and health purposes. Hell, one alien had been on the verge of discovering the cure for cancer before a gang killed him.
It was ridiculous, but that was how things were.

The aliens had learned, for the most part, just to keep quiet. Humans, on the other hand, were relentless. They never saw the bright side of the situation, only focused on the fact that the aliens were different. Apparently, too different for the humans to associate with. When the aliens first arrived, most of the humans just kept your distance. After awhile though, they started to get fed up. They started treating the aliens as just that: aliens.

For some, it was mild. They would just act like they weren't there, or treat them as you would a childhood friend that went sour. For others, it was more extreme. Some humans would get together in very large groups, with their only mission being to attack, maim, or kill, if possible, any alien that they happened to see. These gangs would hold meetings in surprisingly public places. Most believed it was just a way to intimidate the aliens, but some knew that it was the gang's sole purpose to try and exterminate the entire new race.

I know all about those gangs. No, I'm not part of one. I would rather be tortured vigorously for years before given the gift of death, than be a part of something so vile that their only happiness in life comes from killing others. No.

I'm their target.

I'm an alien.