But everybody that became wealthy took advantage of systematic injustices to do so (and to keep his wealth).
That seems a bit of an overstatement, unless you're going to argue from extremes, eg 'X chose to work at building a business rather than establishing a level economic playing field for everyone before starting that business.' I've met lots of privileged people, but I've also met a lot of people that succeeded through a mixture of luck, talent and diligence and I don't consider them to be taking advantage of systematic injustice.
There's a recent quote going around, that if you are male, white and middle-upper class, you're playing life in "easy mode".
Now, this means you get resources from others, those that are playing life in "hard mode". People don't start from equal positions -- and the winners like to think it was their "hard work" and "determination" that got them there. As if a coal miner doesn't work hard, or a single mother of four working at some shitty job to make ends meet is not "determined".
And the higher you go, the easier it gets for you, and the more "cheat codes" you unlock.
Those give you all sorts of powers. Like, firing people. People that own a business fire people that were perfectly good at their job and needed the money, if the company economic conditions require it (whereas, they rarely share their loot when the company makes a killing).
Or take collecting rent. Another injustice. Beginning from an empty land (actually a land inhabited by indians, that were driven out the lands, but I digress), somehow one person now has 4 apartments, and another person has to pay rent to him.
Now, that's a high level view - imbalances and injustice is all around. Even holding on to money, with people starving, is injustice enough in my worldview.
I think what the grandparent means is that the fundamental imbalance of the present system (for example, some are born in to greater education and more supportive environments, with greater access to resources) is self-perpetuating. Ignoring the real impact of the system as a whole is morally questionable.
Coming from a luckier background and accruing wealth without making efforts to alter the system is essentially tantamount to supporting systematized inequity and is therefore morally questionable.
Likewise, being poor in a wealthy country but consuming vast quantities of resources, whining about how the 1% is the problem whilst personally producing serious negative effects on the shared environment is also morally questionable.
Many philosophies (eg. Buddhism) eventually get to the point, deducing from there, where it is realized that we are all inherently destructive creatures. Our mere existence is the destruction of others' rights and resources in our vast yet finite environment. Furthermore, each of us possesses limited time and our capacity for constituting positive change is merely to correctly take charge of our own actions (including thoughts, speech, etc.) in the present.
I'm not sure about the monotheistic religious traditions, but in a philosophical sense Buddha's response to this moral quandry was, IMHO, pretty well argued and pretty damn timeless! It's called The Noble Eightfold Path. If interested there's a good deal more on that from a famous American monk (born in New York) at http://www.accesstoinsight.org/lib/authors/bodhi/waytoend.ht... and from a Burmese monk at http://www.bps.lk/olib/wh/wh245-p.html
That seems a bit of an overstatement, unless you're going to argue from extremes, eg 'X chose to work at building a business rather than establishing a level economic playing field for everyone before starting that business.' I've met lots of privileged people, but I've also met a lot of people that succeeded through a mixture of luck, talent and diligence and I don't consider them to be taking advantage of systematic injustice.
Can you explain what you mean?