There is an epidemic in this country of parents not financially supporting their children. Custodial parents often struggle to support their child(ren) with one income. It is very difficult to have a child support order enforced. Local governments often do not have the resources to enforce child support orders and there seldom are consequences to parents who refuse to work and pay support.
Custodial parents who struggle financially must pay interest and applicable penalties on money they owe, yet cannot collect interest and penalties on deliquent payments owed to them.
If a bank holds your money it must pay you interest. If you owe a bank, you must pay interest. Delinquent child support obligors should not be excluded from having to pay interest and penalties on money owed.