Can a creditor who has a judgment against you garnish your wages?

Generally, Yes, of course. that's exactly what garnishments are used for.

The judgment you know is a court order saying you do owe and must pay. Your in direct defiance of the law by not doing so. It would seem you really have no right to even suggest you shouldn't be forced to pay all that is due, anyway possible for them to get it. And yes, you will end up paying all their costs of collecting it...which is also fair.
At present four U.S. states - North Carolina, Pennsylvania, South Carolina and Texas - do not allow wage garnishment at all except for debts related to taxes, child support, federally guaranteed student loans, and court-ordered fines or restitution for a crime the debtor committed. Normally the maximum is 25% of wages.