The guy had absolutely nothing of a value to add. He did have a politcal axe to grind. Mr Vindman is a fraud.
Trump does not have a Constitutional obligation to retain those on staff who undermine him or worse. Trump has a country to run and needs people to perform according his obligation to fulfilling his campaign promises to voters as well as his other obligations of office.
https://thehill.com/policy/defense/...ntagon-policy-chief-resigns-at-trumps-request Overnight Defense: Pentagon policy chief resigns at Trump's request | Trump wishes official 'well in his future endeavors' | Armed Services chairman warns against Africa drawdown after trip Rood played a role in the Ukraine aid drama at the center of Trump’s impeachment. He certified to Congress in May that Ukraine had taken necessary anti-corruption steps to merit giving them $250 million, undercutting Trump’s argument that he held up the aid over concerns about corruption.