And let's face it there isn't much irony or satire about the Chaos Dwarves or Pygmies (Floating Gardens excepted, there is something different going on there), they are just reproducing the stereotypes.
It's quite astonishing how almost exactly the same characters as Chaos Dwarfs are being used in an anti-semetic way today.
Skulls for the Skull Hat! or something, and on a historical note, Assyrians are semites, maybe different to Jews, but it's called anti-Semitism for a reason, lumping them all together is part of how stereotyping works.
The problem with promulgating racist stereotypes is that whilst we, personally, might be above such matters, they will be read as "racist" by racists, and will see the argument "it's all just fun and games" will be seen as complicity with their viewpoints. Actively subverting those views, well then yes, maybe we're on to something interesting.
Similarly racists love things like Star Trek where aliens are shown as "racial monocultures" - all Klingons are Warlike, all Ferengi are Greedy, all Jews are... etc. because it supports their way of organising the world. Although I will go on to say that Trek, Starwars, B5 have at their heart a multi-cultural team of heroes, who are distinct, and contrasted against a the undifferentiated mass of alien others. Warhammer (3rd ed onwards) doesn't do that, it has racially segregated armies.