Gangplank's barrels ignore some armor and deal bonus physical damage right? If Fiora's passive did the same thing then your armor wouldn't be totally useless and she could still do tons of damage. It wouldn't really stop the tank build but it would offer some counterbuilding at least right?
Baby Ghoul1 votes%health true damage is supposed to counter tanks.
Tank Fiora is a problem, but %health true damage needs to exist so that super tanks don't dominate the game. You'll find the majority of champions that do well against Fiora in lane are not tanks or do not build tanky. That's why it's really silly when people other than tanks complain about it.
They're fighters like 
or marksman like 
, and even mages can work 
. Some tanks can make it work, but usually you want a fighter, mage, or ADC against her.
