The immigration situation in this country needs to swing a bit to the right. Part of the problem is that giving some rights to illegal aliens is necessary, so there's a tendency, particularly on the left, to give them rights of citizens. Not good.
This clause provides a source of rights for illegals, er, uninvited guests, without tending to let them run for President. Never mind that Obama/Soetoro has no proper papers. That's dealt with elsewhere.