This question has been closed as a duplicate because it has an answer elsewhere, but anyone who wishes to write a new answer is most welcome to post it under the original question, possibly referencing this question in your new answer to avoid any confusion.
I have heard some people insult others explicitly with the rider "I would never call" which is a meaningless denial in context because the person is effectively calling them that right then and there, as in
I would never call you a dull, idiotic bigot...
I would never call my learned opponent fat, ugly and ignorant...
Alternate form kindly reminded by @Fattie in a comment:
"Many people have said she is XZY [insult] - but of course I'd never say that!"
This is often heard in a political context but also in personal interactions. Is there a word or phrase to describe this?
Phrases I have considered and rejected: It is not a veiled insult or a qualified insult because the insult is not veiled/ qualified but explicit, and it is not a backhanded compliment because it is not a mitigated compliment or an insult with potential to carry a compliment, but is an outright, unmitigated insult.
Update: Thanks to @Edwin Ashworth for marking as duplicate and pointing to the earlier question: of those 4 answers the word apophasis seems very appropriate for this context based on the insulting political examples provided in the article linked: https://thoughtco.com/what-is-apophasis-rhetoric-1689115