Originally, these provisos permitted the use of LSC funds for legal assistance to an alien if the alien was a resident of the United States and fell within one of the permissible alien categories, all of which required that an alien was in lawful status.
Many people that aren't legal citizens come to the LSC for legal help. 
mnli hypothesis: Many people that aren't legal citizens come to the LSC for legal help.  premise: Originally, these provisos permitted the use of LSC funds for legal assistance to an alien if the alien was a resident of the United States and fell within one of the permissible alien categories, all of which required that an alien was in lawful status.