Why does Nasus get nerfed for his sustain yet the new Keystone is allowed to exist?

Champions like and are even more stupid to lane against since they get infinite free sustain with the new keystone since they get massive amounts of crit from their passives.

The mastery in question is obviously Warlord's Bloodlust. Critical strikes heal for 15% of the damage dealt and grant you 20% attack speed for 4 seconds (2 second cooldown).

First of all, almost every single other keystone requires the target to be a champion yet this one allows you infinite free sustain from minions which is a pain to deal with in lane (and monsters for jungling infinite sustain), especially when dealing with champions like Trynd and Yasuo, who are already oppressive in lane. And then on top of that it gives free attack speed which lasts longer than the cooldown.

Also this mastery scales incredibly well into the late game again ESPECIALLY on trynd and yasuo but also on ADCs so its not like its just an early game lane sustain thing, it just scales even harder late making them incredibly difficult to kill and increasing their DPS by a lot.

It's bad enough with the AP item nerfs (especially to Zhonya, which could be used to counter these AD champs) and the increased crit from items but they have to add this now? Like really. Way over the top. This mastery is WAY too strong.