We humans tend to never learn from any of our mistakes that we have made from the past. Our species repeats the same mistakes over and over again. Genocide, slavery, classism, fear mongering, War, you name it. Humans have done it thousands of times and we have never really learned from it. Nor I believe we never will, as history shows us.
Unfortunatly this realization is completely true. It's a sad realization really, that our species is nothing more than ignorant oblivious viruses, infecting the planet, and soon if we even become just somewhat intellegent as a species, we will soon infect the rest of the universe in time. That's if we survive long enough.