Just about every person has asked at some time or another in their life, if aliens are real then why haven't they contacted us? I've heard this question a dozen or more times, I've asked myself the same question in moments of doubt in regards to the possibility of intelligent life existing on other planets. It's not an unreasonable question. It's also one worth contemplating various theories for. My theory is, why would aliens want to contact us? It's kind of like this, if a new family moves into your neighborhood you might get the idea to go over to their house and introduce yourself.
If however upon your arrival you should discover there is evidence of domestic violence and / or drug abuse taking place in said home, you'll probably quickly turn around and walk away hoping no one saw you stopping by. We as a race in general do not like ourselves or eachother. The proof is in the endless violence and killing, we hunt animals to extinction, we pollute our environment, we continuously find reasons to fight. After all our evolution and supposed advances in science and technology we fail to find a method for establishing peace, our leaders spend billions of dollars each year developing bigger, better newer and more creative methods of fighting wars.
Is it possible we could perhaps instead spend all that money trying to find methods of creating peace and harmony? Nope. I know it's an dumb question. Aliens probably wouldn't like us, we probably wouldn't like them either.
Until we can get along with ourselves and each other, Aliens most likely wont want to try and get along with us either. Maybe It's not that they haven't made contact, it's that they are simply just giving us the cold shoulder.