Because he just makes things up.
In the second debate, he said that all rich people use massive tax deductions, like the carry forward loss write-off, and he specifically named Warren Buffett and George Soros.
Buffett took exception. He issued a statement that he paid federal income taxes every year since 1944 when he was 13 years old.
Buffet, with an estimated fortune of over $65 billion, is about 20 times as rich as Trump, at $3.7 billion, according to Forbes.
My 2015 return shows adjusted gross income of $11,563,931. My deductions totaled $5,477,694, of which allowable charitable contributions were $3,469,179. All but $36,037 of the remainder was for state income taxes.
— Warren Buffett
More poignantly, Buffett says that his total charitable contributions for the year were $2,858,057,970, of which “more than $2.85 billion were not taken as deductions and never will be.”
To put it into perspective, Buffett, in 2015 alone, gave away 75% as much money as Trump’s entire net worth. In one year alone. And he didn’t get a deduction for it.
Trump, in his defensive statement, just made things up. And Buffett wasn’t having any of it.
And neither am I.