Personally, i find that we, as a species, are programmed to be in a moral grey, it is not the fault of the individual in my eyes; people lose their way due to the failures of society to demonstrate the correct way to act. School is a big example, the lack of a functional penal system to prevent bullying allows for thugs to throw their weight around and think its okay, as a sufferer of bullying when i was younger, i can partly relate to your disillusionment with people in general due to personal experience. However, i refuse to believe that humanity as a whole is evil; in certain occasions, we witness the dark side of humanity: murder, extremism, rape, etc, etc, but no-one ever talks about all the humanitarians out there, the charities that help those in need.
In this world, it is far to easy to give into hate and to refuse to trust other people, but that is exactly why we have this problem, that same disillusionment you feel means that the cycle will forever continue. It may be hard to swallow, but in order to prove humanity is not evil, you need to stop looking at the evils of the world and look at the good. Others may hate one another but i physically cant just conclude everyone is evil, if someone were to get into an accident and i was there, i couldn't just ignore them. Rise above anger and be what others couldnt: A person who lives for others.
"Only a life lived for others is one worth living" - Einstein