To be honest, until I saw the first TV promo ("Deep Throat revealed, but is he a hero or a traitor?"), it never occured to me that this was a controversial question. It is hard to believe that the country has changed so much over the last thirty years that this could be seriously debated. And yet it has, and it is.
Felt did not bring down President Nixon, the truth did that. Felt helped the truth come to light. Those who argue that he should not have done so are arguing that Nixon's crimes should have gone undetected and unpunished, that loyalty to the chain of command is more important than loyalty to the nation and its laws, that the highest value in the land is in fact fealty to authority.