I've heard this theory before, that each player's profile has a random exotic weapon and/or armor with an extremely low or even 0% drop rate. Which very well could be the case. But I find it difficult to believe this. I think it's more likely that, since exotic drops are rare as it is, that the odds of getting the one thing you are looking for (out of a dozen or so) are fairly low, and people want to try to find meaning in everything, to know the reason why something is (or isn't) happening, so they come up with this theory which would certainly explain it. So now with is idea that there is still nothing you can do about it, at least you have someone (Bungie) to blame for it.