I can tell you that on the federal level, all prospective employees are put through the wringer. I was tested for better that twenty drugs, both illegal as well as commonly abused prescriptions. They also performed a complete background check, right down to unpaid parking tickets. Also, my fingerprints as well as other biometrics are now in every major database in the country, even though I have no criminal record.
Anyway - If you want some of the republic's money, then the republic has the right to know exactly what they are paying for. If you disagree with the terms, then don't apply for a federal job. The same should be true for those on a public assistance program. The taxpayers have an interest in knowing that their money isn't being invested into illegal activities. If you have a problem with this, then don't apply for welfare.