I've already explained why. Why do you care? I don't like to call myself an Iranian because the revolution (when we became Iran) fucked everything up. Now Iran is a terrorist funding islamic fundamentalist country that I don't assosiate myself with.
An indian called herself persian? Why? 
Exactly, don't want to call yourself Iranian because Iran is a terrorist state. What would happened if Iran became a global ecomonic capitalist (democratic) nation? Would call yourself Iranian then? Chances are like every other ethnic group that has a negative stigmatism to the name, once something positive happens they embrace that culture that nation.
kinda like the black people who say they are mixed with everything else (Native American, Italian, Puerto Rican,etc.) just to say they are "better" than those who aren't, or scared to aknowledge that they are black...Period.