You didn't earn yours. You just got lucky. There is no such thing as earning anything here on destiny unless you buy it from any vendors. INCLUDING Xûr. To get anything they have, you have to work for them and get special things needed such as glimmer, marks, strange coins, motes of light, etc. everybody who says they earned all their exotics from raids or the Nightfall just were lucky. It is all random so deal with it scrub. It's all in the favor of the RNG. There is nothing else to it.