Earlier quoted context omitted.
humor with the intention of ridiculing something by using its own tropes to the point of absurdity to show the wrongness/badness of the thing is a well-established form of satire and commentary. a satirist is emphatically NOT in concordance or agreement with that which they are satirizing. I find it unreasonable that you are arguing against this basic premise. Maybe I'm misunderstanding you. I hope I am because If I…
You're assuming the people employing that black humor don't believe what they're saying. I, and I expect the person to whom you reply, don't adhere to that assumption. I think that "just a joke", in this context, is the exhibition of profound naivete. And even if the speaker realizes it's a joke--the listeners often don't. See the /pol/ commentary elsewhere in this thread; /pol/ was "just joking" until those jokes we…
/r/dankmemes has similar subject matter but it's clear that it's ironic and it's black humor.
They are two fundamentally different things. Nobody is being indoctrinated into being a fascist from the latter. The former is actively attempting indoctrination.