The nuance is that Buffett's tax profile is largely a feature of how he makes money through investments and the relevant tax code. I'm betting that if Trump were to have a similar asset profile, Trump's results would be similar.

From another article:

  "[Because BRK doesn't pay dividends, ...] the Treasury has been 
  getting exiguous tax revenue from one of its wealthiest citizens. 
  Buffett is virtually immune to higher individual income-tax rates, 
  while he promotes higher rates for other rich people, who may 
  have a net worth a hundredth of 1% (0.01%) of his own."[0]