How very different is it when the order that was refused to be carried out was lying? In this scenario, someone was fired for effectively not lying. For that person to then make the claim that one could reasonably expect their successor to do the lying they were unwilling to carry out is only logical if they wanted to keep the job. Sure, perhaps calling them "liars" is harsh diction. But what's unprofessional is firing an employee because of their integrity in regards to the truth, especially pertaining to public safety

There are no perfect whistleblowers. If you're looking for something that destroys their credibility, you'll always be able to find one. Your particular complaint here is purely aesthetic and I think we'd all be better off focusing on the substance rather than going ten rounds about word choice and tone.