The reasoning assumes their is a moral reason to have the object or that it can have a moral purpose. Some guns for example have no private moral purpose and therefore would not be protected by my statement. For example a m16 has no private moral value. If you need that much firepower to kill a deer you need a new hobby.

A side note: It is also possible for something to be justifiably illegal and yet not be immoral, basically because people can't be trusted to use it correctly.