Question: Official term for "whataboutism"?

At first blush this may seem similar to a classic tu quoque logical fallacy (subset of ad hominem), which usually applies to the inconsistency of a single individual’s assertion or behavior.

Fred: “You shouldn’t eat fried food, it may cause heart disease.”
Mary: “You eat fried food all the time.”

The fallacy lies in the Premise (fried food causing or contributing to heart disease) not being invalidated by the inconsistent behavior of the asserter. (Note: the Premise may or may not be objectively true; this is irrelevant to the presence of a logical fallacy)

The OP’s example is a bit different:

Person 1: John is setting a bad example by jay walking in a school zone.

Person 2: What about Delores? She jay walks wherever she goes.

Differences are:

1.There is no reference to an INCONSISTENT assertion or behavior of the asserter, Person 1) who is making a statement (Premise) about another individual’s (John) “bad example.” Rather, another party (Delores) is subsequently introduced.
2.(More importantly) Person 2’s reply is neutral. It is not asserting an inconsistency with Person 1’s premise. At most it is ‘Jumping on the bandwagon’ (i.e. Dolores is doing the same thing as John) - falling short of an attempt to either validate or refute this Premise.

Given the above, I see no evidence laws of logic were violated, thus I see no logical fallacy.