Classes and Sub-Classes: Until You Title Them By What They Do, People Will Continue To Get Mad..
Called a Tank, Builds tanky, IS tanky.. but does damage, a good amount of damage to be considered a Vanguard ("Offensive tank) atleast, not a Warden ("Defensive Tank"), If not Juggernaut.
Src: https://gyazo.com/17fdd2d953f0a53a4b6a3d44af7e22f2 Subclass Definitions
Src: https://gyazo.com/85960d969bf6fe72687f98ca20edd277 Poppy's Placement
called a marksman, Builds marksman, is an Assassin, 3 shots squishies after 25 minutes, basically promised AS you pick Vayne , and does the same to tanks(except it take 6 shots)
Src: Biased Vayne Montage
https://www.youtube.com/watch?v=ivcCkPUeXy4
EDIT: This post was originally about just the Tank class (thats why random anime gif) but realized theres more than one class that fits this issue.
( ͡° ͜ʖ ͡°)
is a diver because her Q is a dash forward (or maybe not, shes getting roster worked) its about how you use the kit, not the kit itself, without subclasses, poppy is a tank, that has spammable maximum health damage, if you use her strictly as a Warden you aren't using Poppy to her potential that means she ISN'T a Warden innately.