Then, to answer your question: Things are taboo when they identify the speaker as an outsider or otherwise excessively different from the main group. Subtexts like “I am not embarrassed to talk about sex.” or “I am a racist.” or “I do not believe that Eliezer cannot be very wrong about something that he has considered carefully.” are taboo wherever the perceived social identity is contrary to that.
ETA: A simpler question: Is there any sentence one can speak which communicates only the content of a claim which has an objective truth value, without even implying that the speaker endorses the claim?
Then, to answer your question: Things are taboo when they identify the speaker as an outsider or otherwise excessively different from the main group. Subtexts like “I am not embarrassed to talk about sex.” or “I am a racist.” or “I do not believe that Eliezer cannot be very wrong about something that he has considered carefully.” are taboo wherever the perceived social identity is contrary to that.
ETA: A simpler question: Is there any sentence one can speak which communicates only the content of a claim which has an objective truth value, without even implying that the speaker endorses the claim?