The protest angle in this is it seriously slows the amount of income taxes being collected by the government until that time when taxes are due (typically April 15th, but with legal extensions, this can be postponed). The goal is to slow the amount of money going on a regular basis into the US Treasury. Oh, they’ll eventually get the money, but it won’t be before it is legally due.
It’s ridiculous that a family of four, earning a combined income of less than $60,000 from three or four low-paying jobs, with two cars and a mortgage, must employ the services of a certified public accountant in order to file its income taxes once a year.
Russia instituted a flat tax of 13% in 2001 and greatly increased its tax revenues to the national treasury. Not only that, President Putin lowered the corporate tax rate in Russia from 35% to 24% and further increased revenues to the treasury.