The difference, is one's intentional, the other is about how it is sometimes hard to tell which is intentional. The movie adaptation of Star Ship Troopers was purposefully not like the book
because the producer felt the book was glorifying fascism. The movie set out to do the opposite, make fascism look bad. This it undeniably did(the soldiers are ill disciplined, their tactics are horrible, the drive of their entire society is questionable) Poes law come in that many people missed the parody part, and just assumed the film had a horrible writer who knew nothing about the book and wanted to promote fascism.
Dolemite was supposed to be a parody of black exploitation films of its time. The protagonist's only redeeming trait to a modern audience is that he isn't guilty of what he's accused of, but he's guilty of plenty, arguably worse crimes no one seems to care about. He's constantly spouting nonsensical speeches which no one can really complain about because he's pretty much invincible in combat, even though he really shouldn't be
and is altogether unpleasant. That isn't arguable but many people missed the parody and just assumed the writer had wrote up a particularly bad, straight example of an exploitation film. If they knew those who knew the writer knew Dolemite was usually the antagonist in most of his stories so saw the parody right away.
is a trope, Poe's Law
is an audience reaction to stealth parodies. Does Stephen Colbert really that much against the other political party or is he parodying people who are against the other political party?(He's an actor playing an entertaining character on a fake news show but because of Poes law, people can't leave it at that) We should be getting rid of Poe's law before we do anything to stealth parody.