This completely ignores that outside forces will limit what choices a person can make and affect their chance of success.
No matter how hard I try I won't be able to become the president of USA (or many other countries) legally.
In theory I have a chance of getting elected in Finland but my education, family, work history, appearance and connections will have more effect on my odds of winning the elections than just my sheer will.
EDIT: And the main reason this upsets me is that people use it as an excuse to blame the less fortunate ones. "What's that? You are poor and sick? Well why didn't you raise yourself up by your own bootstraps?"
This was on FB and when someone pointed out that the average trash collector in Laos does not have a life full of possibilities he was countered with "Dear old friend, I see what you are saying, but what if I told you that I just met an ex-Laotian trash collector yesterday who is now a multi-millionaire... One person sees dead ends, the other sees a place to forge a new path..."
Fuck you and your bullshit.