you may be assuming that in 2019 you did it correctly when in fact it may have been was incorrect.
@CatinaT1 's instructions make sense to me.
when you receive a 1099-NEC (or previously a 1099-MISC) for earned income, you are going to get hit with 15.3% tax, regardless of the standard deduction. In a perfect world a W-2 employee's salary / hourly wage is 15.3% less so it works out the same.
