"redistribution should always flow, from a moral perspective, in the direction of the poor and the vulnerable."

Is there a limit, though, from a moral perspective? For a single person, health insurance premiums that mostly subsidize care for the elderly and indigent can easily take up 10% of their income. Tax withholdings, again mostly for elderly and indigent care, take up another 12% of their income. Of course, social justice also requires charity to the poor or tithing to the Church, which would be another 10%.  At this point, you've taken a third of a person's income for social justice. Is there a point where all this taking becomes unjust?