That argument is nonsense. It is a standard talking point by the people waging this class warfare thing on the side of the rich.
Nearly everyone who works in this country pays payroll taxes which range from 10-12.5% since Regean jacked them in the 80's. Payroll taxes alone are nearly as high a percentage as the 15% rich people pay on capital gains.
Then there is sales tax, the lower classes spend most of their money, while the rich invest most of theirs so the poor once again pay a disproportionate burden of these which is why its called a regressive tax. The rich want even more sales taxes (aka Value Added Taxes(VAT's) because they regressively punish people who spend and give the rich a free pass
Payroll taxes used to be a couple percent before Reagan jacked them. Social security in particular started producing huge surpluses then that were used to fund Federal budget deficits for decades, in Reagans case to squander money on weapons that were never used. The so called "Trust fund" was completely squandered. To pay for social security and medicare now we either have to tax people some more, borrow it or slash benefits.
Most seniors who retired in before the 90's put almost nothing in to SS and Medicare and are getting windfall returns. People who started working in or after the 80's have been paying taxes through the nose for programs that will be bankrupt and probably gone by the time they retire. It has become a massively regressive tax on young working people to support often affluent seniors.