First of all, the one thing has nothing to do with the other. If you want a nerf to Ahri, one thing, but that doesn't mean, an Azir Nerf is wrong. Two completely different champions, that have nothing to do with eachother.
Secondly, Azir is Pick-Ban in competetive play, and has been for quite a while now. I'm pretty sure to remember, that, when Ahri and Lux were played in the LCS, you used it everytime as an argument, that these champions had to be nerfed. Although they were not even played that much.
Well, Azir has a 90.2 Pick/Banrate at MSI, with 8 Bans and 28 times played, which makes him the fith highest together with Kindred, and only Ryze, Lucian, Maokai and Ekko having higher numbers. (Incidentally, every single one of this champions is also recieving nerfs in this PBE-Patch.. one could almost assume, that there is a pattern) According to your own, earlier argumentation, beeing played that much in Pro-Play is an indicator of a too strong character, that needs a nerf.