What do we call this type of discourse?

Someone, guilty of a wrongdoing, defends his position by reminding the accusing party that, at some point in time, s/he was guilty of the same wrongdoing too. This is instead of making an apology or a promise to change behavior in the future. What do we call such a discourse?

Speaker A: You treated the audience with disrespect (The guilty part does not deny the accusation)

Speaker B: Yes I did, but did you never do the same thing? (Suggesting that Speaker A isn't in a position to make accusations)

Now, I have considered using many phrases and expressions like "fault-finding," "blame game," "finger pointing," "cherry-picking," and "apologetics." While they are 'close' to what I want to say, they all roughly connote an act of defense by denying guilt and laying it on someone else (usually the accuser), as in "You did it, not me!" What I am looking for, however, is a word/phrase suggesting that the accused party indeed admits guilt, but tries to ameliorate his position by saying something like "Hey, but I am not the only one. You did it too."

They would be committing a "tu quoque" logical fallacy, where they do not deny guilt, but attempt to mitigate criticism by pointing out that the accuser is also guilty.

Tu quoque (/tuːˈkwoʊkwiː/; Latin for "you, too" or "you, also") or the appeal to hypocrisy is an informal logical fallacy that intends to discredit the validity of the opponent's logical argument by asserting the opponent's failure to act consistently in accordance with its conclusion(s).

See also here and here.

Since you have mentioned an "audience": in a televised debate, a common strategy is to attach negatives to one's opponent, and to offset negatives attaching to oneself by attaching the same negative (or an equally damaging one) to the opponent.

Mudslinging is a term used to describe this type of discourse.