What kind of a leap of logic is this?
A pretty good one actually. Taxes & the costs of complying with them get passed on by business(the affluent being the owners thererof) and embedded into consumer prices, the point of the article remember?
Under the income/payroll tax system, those in the lower wage brackets not only get hit with income and payroll taxes at the front end reducing their discretionary income, they must expend nearly all they receive merely surviving with little to nothing left for investment above and beyond a hand to mouth existance. As a consequence the current income/payroll tax system impact the lower income brackets in a disproportionate manner, in comparison to those better off who have something left for investment after meeting survival requirements.