Darxul Comments on Political Argument

One breezy sunny day at the park, the aging Darxul was approached by a young political activist who handed him a brochure supporting his candidate and attacking the candidate's opponent.
     "I don't believe I can support your candidate," said Darxul, "because he is a liar."
     "All politicians are liars," said the activist.
     "Tell me something," said the old man; "how much education do you have?"
     "I have a college degree," answered the activist, a bit taken aback. "Why?"
     "I was afraid you would say that. During your college career, did you ever study critical thinking?"
     "What are you implying?"
     "Your statement that all politicians are liars is a poster child for poor thinking."
     "But it's true."
     "Let' think about the statement. The first error is that the claim is unknowable. We simply cannot know in any objective way that all politicians tell lies, or that a certain percent do, and so on."
     "Just listen to them."
     "Second, the statement is a sweeping generalization that is almost certainly false, as many such sweeping generalizations are. There are certainly a few, and possibly many or most, politicians who are not liars."
      "I'd like to meet one sometime," sneered the activist.
      "Third, the claim implies a tu quoque type of fallacy. Your implied argument is that because other politicians tell lies, it is justifiable for your candidate to tell lies. If telling lies is wrong, it is wrong for everyone, regardless if other people lie. You wouldn't argue that because other people rob banks, it's okay for you to rob a bank."
     "You're changing the subject. We're not talking about robbing banks."
     "I was using an analogy. The logic of the argument about banks is analogous to the argument about lying. At any rate, the fourth logical problem with the argument is that it does not distinguish between degrees of the offense. For the sake of argument, let's say that all politicians do tell lies."
     "See? Now you agree with me."
     "Even if all politicians have at one time lied, their culpability is likely much less than that of  a candidate like yours, who tells one lie after another, many of which are enormous fabrications."
     "But all politicians lie," said the activist.