We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
It's the old "So's your old lady" from the schoolyards of yore. It is a primitive and immature, but often effective, fallacy.
Like most fallacies, Tu Quoque subsumes aspects of other fallacies: Ad Hominem, Red Herring, etc. Tu Quoque appears to brings doubt upon a claim by pointing out a real or imaginary problem with the claimant rather than responding to the claim.
It is a perfect type of fallacious argumentation for relativists: "You Americans think you are virtuous, but you had slaves 150 years ago - so don't preach to us about virtue."
"You complain about civil liberties in China, but meanwhile you torture and abuse prisoners in Gitmo."
"How dare you criticize my American Express bill when in 1989 you went out and bought yourself a Corvette."
"Don't talk to me like you are so perfect."
Tu Quoque. Shut them up and put them on the defensive, while ignoring their point. Excellent for ignorant juries, and also perfect for marital disputes - keeps them going on merrily for years.