Background: I, an Australian, once had a co-worker in North Carolina who would often use Southern-US idioms that confused me. I spent an evening panicked about how to handle "This dog will hunt" as feedback on a document before he clarified that meant he was happy with it. Oddly, the phrases always seemed to involve dogs.
So, when a politician from Florida recently used the baffling expression "A hit dog will holler" I wasn't surprised.
Wiktionary explains its figurative meaning:
An offended or defensive response to a statement suggests that the statement applies to the person complaining.
If I understand this correctly, it is like the schoolyard taunt: I'm rubber, you're glue.
But, I understand why the rubber (the insult bounces off me) and glue (the insult sticks to you) idiom works.
What does the yelping of a beaten dog got to do with tu quoque claims?
[Stop Press: A commenter below suggests that I have misunderstood the figurative meaning, even before we get to the literal meaning. Please set me straight on both in an answer.]