The reasons why aliens probably haven't communicated with us are vast, just to name a few:
Maybe some higher galactic power has deemed Earth too primitive and has declared it to be off limits.
Maybe we have been contacted by aliens and the Governments have an agreement with them on disclosure which gives them time to prepare the population for this revelation.
Maybe they don't want to make contact with race that is still killing one another and is recklessly experimenting with nuclear bombs/power. Do you want some primate in space wielding nukes, I don't think so!
And maybe our unprotected transmissions (broadcasted for little over 100 years) hasn't reached an advance space race yet. And what if it reaches a hostile race?
And the list goes on. I think we need to end our wars here on Earth first before we take our stupidity to the stars. Then we can focus the money we spent on wars into mining the asteroid fields (eliminating threats of asteroid impacts) and paving/paying our way to Star Trek like exploration.
Only time will tell, here's hoping for a bright and peaceful future : )
As always I upvote/follow resteem those that do the same for me as long as you don't spam up my feed.
Yes, that's exactly what I have tried to say as well. We need to change our ways.