Has anyone actually read that article? If so, then point out exactly where Buffet is lying. What direct quote from Buffet in that article is false or an outright lie? Notice the bold/italicized text? Neither sentence is in quotation marks, and they are two completely independent sentences. Yes, Buffet was taxed at about 17.7 percent of his taxable income. That he didn't go into detail about the difference between capital gains tax vs. income tax is irrelevant. Why should he? Why should he have to explain an accurate statement to a like-minded crowd of deep-pocketed campaign donors who have already ponied-up the money to be there?
If he were campaigning for a politician, and asking people for their vote, then you might be able to make the argument that he should have explained the difference between capital gains tax and income tax in more detail. And as for the part about his secretary's tax rate, that sentence is completely independent from the previous one, and is not prefaced with a "Buffet said" qualifier. That sentence is the journalist's words, not necessarily Buffet's. And the writer even qualifies that statement by saying "about 30 percent." If you took this before a court and tried to convict Buffet of perjury based on the evidence in this article, you'd be tossed out on your ear.
Why am I going to the trouble of defending Buffet again? Because, if you can read that article, and say with a straight face that Buffet actually lied, then there's no point in even trying to have an honest debate about other substantive issues, because that means you're willing to ignore plain and simple facts in an attempt to discredit the opposing viewpoint.