That is the purpose. People don't like to talk about how class-based US society remains. People, voters, actively want a hierarchy of citizens. Everyone is grouped into neat permanent boxes. There are the "illegals" who live in constant fear of arrest. There are "felons" who can only work certain jobs. There are "sex offenders" who can only live in certain places. Even for free, law-abiding, people there exists a hierarchy of citizenship ranging from "US national" to "citizen", with "native-born citizen" being at the top. Imposing lifetime financial burdens on criminals just creates another underclass of perpetually indigent persons. That is the goal of the policy and reflects the desire of a great many powerful people. Lack of social mobility makes powerful people feel safe. For a while.