Personally, I don't think there is a pragmatic use for passports - the potential danger of the undocumented is so minute that the most pragmatic approach to minimizing danger would be to limit yourself to no interaction with anyone, rather than placing that focus on the undocumented. In other words, there's no sense to targeting the undocumented as a way to minimize danger - everyone is more or less equally dangerous.
Additionally, and perhaps most obviously, we can consider moral ethical reasoning - undocumentaphobia is wrong, for it places fear from a lack of documentation which has no basis for that assumption.