The kind of abstract cognitive pursuits that occupy us in the modern industrialized world are comparatively recent developments. For the vast majority of human history, life has been about simple survival. Both our minds and our bodies are adapted to that task – to make sure that we don't freeze or starve to death, to avoid things trying to kill us, and to make choices that promote our self-interest. That you are here today as the culmination of a million years of human evolution is a good indication that your brain is hard wired for survival.
In a complex world in which many of us are lucky enough to avoid worrying about survival on a daily basis, we have adapted our cognitive abilities to contemplate more abstract concepts. We're capable of understanding things like philosophy, religion, politics, and relationships. But old habits die hard, so to speak. Our minds retain a nagging tendency to distort or manipulate information in ways that enhance our well being, which is a fancy way of saying your brain wants you to feel better about yourself.
Now. Consider this:
I won't dissect this person's statement, which is almost certainly either selective with the truth or exaggerated. That's another story (and ably handled in detail here). What we see is a very common perceptual bias in action: the "just world" phenomenon, a bias of attribution.
If I am a success, my brain wants me to believe that I have succeeded because I am good – talented, hard working, and so on. The converse is that people who do not succeed must be lazy, talentless, or prone to making bad decisions. It's a basic victim-blaming premise. A common example used with this bias is rape. If we blame the victim, it makes us feel safer. Rather than confronting the scary reality that it could happen to you at random, we believe that if we avoid the behaviors of the previous victims then we will remain safe.
Thus the overly simplistic worldview we see on display in the above photo. We start with our brain's desire to bolster our self-image – You're a big success, Timmy! You've earned all that you have! – and end with a worldview that requires us to assign the same level of responsibility to others. If we admit that external factors such as chance or social class influence others' outcomes, then we would be admitting that the same things might have benefited us. But of course I didn't just "get lucky"…I earned all of this. So don't you whiners go blaming bad luck or forces beyond your control if you're not happy. You've clearly made a lot of bad decisions, the same kind that I'm smart enough to avoid.
It all makes sense now.