Not sure why you wrote “except”. Such government unpaid internships are a signal that those lines of work are highly competitive to get into (just like in lines of work at private employers what unpaid internships are the norm). As with any line of work where unpaid internships are the norm for entry level persons, someone considering those lines of work should be aware of the difficulty of getting an entry level paid job in those lines of work, and perhaps reconsider his/her career direction if s/he cannot afford to do the prerequisite unpaid internships.