The court isn't. If you read the article carefully, it's given as an alternative.

It's also only being applied to deadbeat dads who have more than four children with three or more women *and* who are in arrears on their payments to the tune of a significant chunk of change.

They've already been found (or have pleaded) guilty. The sentence under law is jail time for thier offense. The judge merely gave them the option to choose vasectomey instead. All but one took it. They could have gone to jail instead.

Besides, vasectomy is, to some degree, reversable. If these guys ever really feel the need to reproduce, they can get it reversed.