“take no lectures”

I see that Emily Thornberry in the Guardian says that Labour will ‘take no lectures’ from Theresa May about respecting democracy. God, how I hate this tiresome, snitty, intellectually feeble but rabble-rousing Question-Time-style cliché. Take no lectures. What does it mean? It means, roughly, ‘I don’t actually have much of an answer to your point but I don’t need one because you’re just as bad as me, in fact you’re worse.’ There is a term in philosophy  for this kind of argument: tu quoque (which means ‘you too’). It is a logically fallacious argument, for a proposition advanced by a hypocrite may nevertheless be true. ‘Smoking is bad for you’ is still true even if it is said by somebody puffing on a cigar. Its widespread use in political discourse (and Thornberry is very far from being the only culprit; it’s beloved of both left and right) is symptomatic of our dreadful tribal, adversarial political culture, where utterances are judged not according to their content but according to who says them.