Income is taxed in bands, not all at one rate
The standard deduction comes off first and is taxed at nothing. What is left is cut into bands, and each band is charged at its own rate, with the lowest slice at the lowest rate, and so on upward.
Your bracket is the rate on the final slice. Someone with $100,000 of pay is in the 22% band, but the 22% applies only to the part of their taxable income above the threshold. Everything below is charged less, and the deduction is charged nothing.
