So, how does one respond when a relative suddenly says "And of course, Grandpa was a pedophile!" during dinner? I would like a cool line that smoothly and politely conveys that a topic is inappropriate and segways into something else without creating a confrontation or drama. I don't want to feed the drama llama, but I want to avoid her ruining the occasion or dragging us down to her level.
If that's a literal example, I would probably say something like "I'm so sorry you were abused, are you seeing a therapist?" or "I'm so sorry you were abused, but I think that's a topic for your therapist's office, not Christmas dinner," depending on whether I thought the speaker was in need of therapy they weren't getting. Any response along the lines of "I don't mean he abused
me" would get "Oh, good, then we don't need to talk about it during our holiday dinner."
My figuring there is that the odds are that this is malicious gossip (or thoughtless "pay attention to me!" gossip from someone who figures Grandpa is dead and no longer cares what's said about him), but if not, I want the message to be "I recognize that he did something horrible to you, and we can talk about it later" rather than "don't disturb our belief in a happy family with your suffering."
For a huge range of other topics, yes, go straight to the bean dip: whether a long-dead relative cheated on his wife, or was secretly a member of the Purple religion, or didn't actually graduate from high school isn't something that directly hurt the speaker.