Answer by James Adams:
They're the same reasons you don't make contact with this little guy:
You could, you know. You could do your research and go out into your backyard with vials of ant pheromones and communicate with these guys. You could lead them to food, alert them to danger, and tell them where to nest. So why don’t you?
Your messages would be lost on them. Their crude language would bottleneck your message. Imagine trying to describe the internet with a vocabulary of four words: food, friend, danger, build. would they even care about what you'd like to tell them when their most pressing concerns are heavy rains and raids from neighboring ant hills? For their part, they’d have a hard time even distinguishing your smelly earthquakes and eclipses from Mother Nature.
You’re not interested in what they have to say. Imagine an ant colony that fantasizes about one day making contact with a curious human. They reason that exchange would be mutually beneficial. You could bring them food and they could show you the optimum depth to store your larvae at. How could they know that ant-kind doesn’t even have words for the things humans want?
They are too trivial to merit your curiosity, and you have nothing to gain from them. Meanwhile, you have important, real world problems to solve that take priority over trying to uplift ants with a recitation of Hamlet.
The premise that I’m assuming is that we are to ants as extraterrestrials are to us. It’s not an unreasonable premise. If extraterrestrials exist, it is statistically probable that they are older than us, because the universe has been habitable for so much longer than we have been here. Under Moore’s law, the computers of 2063 will be 30,000,000 times as powerful as those of 2013. If fifty years can do that, how advanced is the intelligence of someone who had JUST a million year head start on us? Trying to imagine it, the mind boggles, sizzles and pops.
If they exist, you have nothing of interest to them.