Tanks are broken?

Not sure if i'm right about this (need opinions) ive been playing league since 2012, i dont recall tanky champions ever doing this much damage or being capable of just dominating games, in normals or arams. But thats what has been happening lately! the game i linked i believe shows how a pre built team of 5 took advantage of this and just dominated our game :/ Ive also noticed this on arams, if their team has 2+ tanks its an automatic win for them. Their tanks have SOO much sustain from warmong's! and then they have crazy damage from IDK where?!