Exactly. We've seen this in responses to (for example) the Rolling Stone fake sexual assault story. Many people said "the problem is real even if this story may not be."

So people may push fake stories to make what they believe to be a justified point.

  Also, it isn't difficult to imagine a future where people are criticized for correctly identifying deep fakes.

I didn't understand your scenario. Can you expand on that?

Saying "the Nixon video is fake" in a community of Nixon truthers will get you verbally attacked? It seems extremely likely.

It's already a common troll[1] to just post "FAKE" in anything where the evidence is difficult/impossible to verify. There's a whole subreddit, /r/NothingEverHappens, devoted to making fun of this troll, and adding politics/culture war to the mix will just make the backlash to people who call "FAKE" that much worse.

[1] "Troll" as in "derailing tactic used by people who don't know or care if it's really fake or not" simply to be extra-clear. In politics, throwing out chaff and using derailing tactics to make it effectively impossible to have certain discussions in open fora can be a good way to prevent inconvenient ideas from being spread, in addition to the usual tactics around sowing uncertainty and confusion among the enemy.