Aliens wont attack us WHY not?

Because there are none.
I would look into the people promoting such trends because
those are the ones doing any kind of attacking.

There are a couple of reasons for why we will never learn the truth.
First of all. Them aliens have read/written Sun Tzu's The Art of War.
Hence they wait, and wait, and wait, just like China does regarding their war against USA. They know USA will be for the takings as soon as USA has been worn down financially. They don't even need to get blood on their hands. It is a pure and devastating financial war.
The reason for why our governments wont have a disclosure on this theme, is that nobody would believe that the wanton supply for kittens is the original reason. What human mind would actually believe that after centuries of war, being told about giants in chariots of fire and such.
Nevermind that after all these years as slaves, we have become psychotic schizofrenics, brainwashed and tortured to believe in devils and sulphurous brimstone when we die.

That would be the day.

I don't think aliens would attack us because pulling mass amounts of resources out of our planet's gravity well would just be too expensive when compared to asteroid mining. There are far greater deposits of minerals and metal to be found in asteroid belts, and they are already conveniently located in very low to zero gravity. In short, we're just not worth the effort.

science.howstuffworks.com...

Corporations that might not be interested in exploring space for the adventure and science could be interested in the treasures that a space mining operation could send back to Earth. One NASA report estimates that the mineral wealth of the asteroids in the asteroid belt might exceed $100 billion for each of the six billion people on Earth. John S. Lewis, author of the space mining book Mining the Sky, has said that an asteroid with a diameter of one kilometer would have a mass of about two billion tons. There are perhaps one million asteroids of this size in the solar system. One of these asteroids, according to Lewis, would contain 30 million tons of nickel, 1.5 million tons of metal cobalt and 7,500 tons of platinum. The platinum alone would have a value of more than $150 billion!