But that's not what he means, and not really what he's writing about. The way I read this, he's proposing a shift in world view. People are difficult and unpredictable creatures, but, if I were smart enough, I would understand how they work. I could have been smart enough or empathetic enough to realize this stranger had a bad day, and say something nice to him to cheer him up. I could have been smart enough to get a better security system for my house. If I really cared about global warming, I could try to become a U.S. senator (or some other powerful politician) and try to change it.
By saying, "It's my fault", what the OP means is, "If I really cared about this, and was smart/strong/etc enough, I could have worked to fix/prevent this". This isn't about "[controlling] the entire world". It's about believing that you have control over your life, and about realizing that blaming others (whether in an angry or forgiving sense) is entirely useless in terms of practicality. If you blame others for anything, you're saying that there's nothing you could've done, and letting others determine your life.
I understand that in some regards, this is a bit silly. It's not my fault that someone had a bad day, and it's not my fault that I don't know them well enough to make them feel better. It's not my fault they were rude to me. But I'd rather pretend it's my fault and think about ways that I could handle the situation better in the future than just blame it on external forces and allow myself to repeat the same mistakes.