Why is olaf just allowd to be in game?

Before anyoen says anything: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2070009524/201402079?tab=builds&participant=7 check olaf's build, check his runes, check his masteries. he has the MINIMAL amount of armour. then check mine, i have flat pen off the tree, with thunderlords.

Having said that, olaf built PURE HP, against a poppy who deals MAX HEALTH SCALING DAMAGE. That means the more HP he has, the more damage i do to him, coupled with poppy's passive, and thunderlords decree, he should have MELTED to me.

Instead, he took no damage, at all. I am 100% dead serious, he took 0 dmaage form me, and my Q. my Q, may i remind you, that deals SCALING MAX HEALTH DAMAGE... TWICE...

Olaf built no armour, yet somehow managed to tank 20k damage, over TWICE what i, a full tank poppy, took, yet somehow he only died ONCE. Not only that, but his slow was basically a perma slow.

You know another champion that has a permaslow, can build pure health and win fights pretty uncontested?

So why is olaf ignored, while tahm gets nerfs? I really need to know, i need to know how a champion with no armour can tank multiple hits from an ability that deals a total of 12% of total HP+flat AD damage, and somehow take no damage at all gets ignored, meanwhile tahm gets hated on nonstop.

So... the TL:DR version is: why is a champion allowd to have an essentially free, no CD permaslow, able to build pure HP and nuke tanks, take 0 damage, and be completley immune to CC, AND do true damage jsut allowd to exist in game?