Think about it. The exotics get nerfed more and more as time goes on, and Xur is the easiest way to get exotics so his are the most common ones. Have you also realized that past year exotics can't be infused? Well I have a theory. You see, the Darkness are stopped by new and new weapons made to fit their current difficulties or dark level, helped by people who study the Darkness like Gunsmith who experiments new weapons. So basically Xur sells his OWN weapons so my theory is the Nine or whatever make all the exotic weapons that have great capabilities at first but then over time they rust and get nerfed more and more!
This may be why then! They want to wait until the standart weapons become so useless because of the growing power of the Darkness that the Guardians will have no choice but to use Exotics but now they'll be intentionally bad even though they can stop the Darkness because they are made by the Darkness (Xur). Also, have you realized that soon after there's a peak of exotic weapon usage in PVP, some/the classes are nerfed? This may be because they're supposed to! They nerf your ennemy over time! It's a secret way to make the Guardians weaker as well to advance the Darkness! This is crazy!
OK so guys, stop buying from that darth xur and use standart weapons! Make sure to tell the Vanguard what you know about them! The Guardians will NOT stand for this! THIS IS A TRICK! A HUGE TRICK! Never use exotics again! They are only made to fool you, which brings me to my next point!
THE NEXT DLC SHOULD BE US TRYING TO DESTROY XUR AND THE NINE.
Who agrees?