There's this attitude, one I'm seeing a lot more of these days (or maybe I'm just more attuned to it than I used to be), that if someone can do something, what's to stop anyone else from doing it? It's a pernicious attitude, in big part because the truth in the statement is ruined by the way it's framed.
Most of how such a discussion is framed is in terms of opportunity, specifically the economic kind. To wit: I didn't get a "handout", but I worked hard and I made it. Ergo, anyone who works hard can also make it; if they don't, it's clearly their own fault. (Notice how anything that could discount the premise — systematic economic problems, invisible advantage on the part of those who did make it, etc. — is conveniently ignored, or downplayed, or invalidated.)
Like all myths, there's a grain of truth in there. Few people get anywhere worth talking about unless they have the initiative to get up and do something. My books and software projects aren't going to write themselves, and they aren't going to get an audience without me doing at least some self-promotion to get them noticed. Valuable things require effort.
Where this whole thing breaks down is when it's used to talk about things on the macro level, rather than the personal level. It's OK to look at your reflection in the mirror and tell yourself you can make it if you try. But to tell a whole society that, or a whole swath of society — especially one that has a rather unyielding first-person understanding of socioeconomic disadvantage — is not sage advice, but a form of mystification bordering on cruelty. It's the same mindset that tells people they can "always find work" — never mind whether or not commuting to and from that work eats up most of their paycheck, never mind whether or not the work itself is life-threatening or heath-destroying or potentially illegal or economically unsustainable. (Has anyone yet coined the term successsplaining?)
This for me is the difference between an article of personal faith and a dogmatic doctrine. The former is something you apply to yourself, and only yourself; the latter is something you apply from you down onto everyone else. And it's also about why you do those things. The former is about building yourself up; the latter is about building yourself up by subtly denigrating others.
Buddhism has five (actually, ten, but five will do for most people) precepts that govern behavior: don't take life, don't lie, don't take what's not given freely*, don't misuse sexuality, don't abuse intoxicants. Parallels are drawn frequently between them and the Christian commandments, but the analogy is not a strong one. The precepts aren't things you lord over other people with, or use to make other people feel like they've stepped out of line; they're things you direct back at yourself. (I suspect the commandments are, at their heart, the same way: they're meant to be things you say to yourself in the mirror and not clubs you use to beat others with.) They're also not inflexible absolutes, because there are times when you might well have to take one life to save thousands — but that's almost never something you can enshrine into a ruleset and expect to be workable across the course of your existence. (More on that some other time.)
Anyway, back to the core idea. It's one thing to challenge yourself and set your sights higher, because you're the only one whose life you have any control over. But the attitude only works when directed inwardly; when turned outwards, all it does is cast aspersions on other people for not being you.
* As my friend Eric Frederiksen pointed out, "'Don't take what's not given freely' depends on people understanding that certain things are not given freely to all people. Opportunity is not given freely, but is assumed to be given freely by many of those who have it. 'Underprivileged' is really a surprisingly accurate term for how long it's been around."