For context (since this reply seems to be getting downvoted into faded-text status at the time I am seeing it, perhaps in part because these days people might be seeing this as a political viewpoint for...reasons):

In Carl Sagan's "Contact" the first message we get from another civilization is a rebroadcast of a Hitler rally in the run-up to the 1936 Olympic games.

In the story, as one of the early examples of broadcasted television this rally happened to be the first broadcast from us that was detected by the civilization at Vega, and they rebroadcast it back to us as part of their larger signal inviting us to come say hi.

Effectively a coincidence that it happened to be fascist in nature, but causing some amount of panic in the story from people who read into this as the aliens being pro-fascist.

"The Message From Vega":

https://www.youtube.com/watch?v=DRD-tO7jV9U