The author of this paper just admitted to being part of an unelected group of individuals who are looking to forcefully impose their ideology on and against the country by active deceit, treachery, and sabotage. If you could avoid letting your views against their target cloud your judgement, you'd see how incredibly broken and dangerous this.

For instance imagine this individual's cabal has an opportunity to engage in an awful act, but due to their position they believe this act will be blamed on the administration or even the president himself. Do you think they would hesitate to do so? This is one of the many reasons that, for instance, in war traitors tend to be treated much more harshly than even the enemy. There's a difference between open disagreement, even when that disagreement escalates into something beyond just words, and an individual that pretends to be an ally and instead is attempting to destroy somebody from within. The latter is already shown to have placed no value on anything except their own world view.

And the purpose of publishing this letter is not to "reassure the public." You should not trust a liar just because he's saying something you want to believe. Occam's razor is highly effective in getting at the truth and in this case it's almost certain that the purpose of publishing this letter is to try to increase the paranoia of the president, and to increase the probability of his engaging in ostensibly irrational behavior. That's just a great idea, right?