But you are not and nothing in your source has proven you so. UI is a payroll tax and part of your total compensation.
http://en.wikipedia.org/wiki/Payroll
Payroll taxes in U.S
Before considering the payroll taxes we need to talk about the Basic Formula for the Net Pay. Basically from gross pay is subtracted one or more deductions to arrive at the Net Pay. In fact Employee's gross pay (pay rate times number of hours worked, including any over time) minus payroll tax deductions, minus voluntary payroll deductions, is equal to Net Pay. As you can see payroll tax deductions play a critical role and just because they are provided by law we can call them Statutory payroll tax deductions.
The employer must withhold payroll taxes from an employee's check and hand them over to several tax agencies by law. Payroll taxes include:
Federal income tax withholding, based on withholding tables in "Publication 15, Employer's Tax Guide"[2] by Internal Revenue Service - IRS;
Social Security tax withholding.[3] The employee pays 6.2 percent of the salary or wage, up to 110,100 (as of 2012). The employer also pays 6.2 percent in Social Security taxes. If you are self-employed, you pay the combined employee and employer amount of 12.4 percent in Social Security taxes on your net earnings;
Medicare tax.[4] The employee pays 1.45 percent in Medicare taxes on the entire salary or wage. The employer also pays 1.45 percent in Medicare taxes. If you are self-employed, you pay the combined employee and employer amount of 2.9 percent in Medicare taxes on your net earnings;
State income tax withholding;
various local tax withholding, such as city taxes, county taxes, school taxes, state disability, and
unemployment insurance.