Benjamin Franklin would, when he heard someone mispronounce a word, make note of it without remark. Later, he would use that same word in conversation the correct way, as a way to correct others without invoking defensiveness. You can use a similar tactic to correct misconceptions.
Another Franklin trick to avoid defensiveness is to change the way you advance your argument. Rather than presenting it as infallible truth, present it as your opinion you’re unsure of, as another point of view, or as something you heard.