The Evolution of Group Mentality

I've tried to understand why this stuff has happened particularly why these things have happened to me. I'm angry it's like why don't you think for yourself but on the other hand it's like well nobody really thinks for themselves. It's not actually very helpful in a small tribal group of 100 to say 300 people to be right if everybody else disagrees with you so it's better to be cohesive. We're at the point human brains are where they should be in terms of evolution for surviving in that sort of environment now what then? What about this new environment where we're in much larger groups we've got social media  it's a highly unnatural environment around usIt's very technological