They are paying taxes. Your first dollar is taxed. However, $400 out of the pocket of someone making $20,000 a year is a great deal more, both as a ratio and as a lived cruelty, than an extra $30,000 for someone making $2,000,000 per year.
Also, as a sidebar, money that goes to the lower quintile is much more likely to be spent quickly in American communities, thus producing more economic growth, while money that goes to the upper quintile is less likely to circulate, and more likely to end up abroad, or sunk into luxury goods. For example, a Hailey Bieber-style ring sends hundreds of thousands of dollars mostly abroad, while an extra $200 for a working mother might translate into better food for her kids and more jobs in her local grocery store.
