I kind of love the logic, really
"AD champs have
all this armor
pen shit
to kill tanks with man. It isn't fair us mages can't deal with tanks after one MR item."
"Jeeze, magic pen
is so
freaking useless
. How are we supposed to kill tanks with these shit items?"
The reason why mage players think they get walled by MR so hard is because they don't remember
actually exists in the game. Flat pen doesn't kill tanks, and the same goes for ap champs. If they're buying a good deal of MR, get a Void Staff.