Regarding the Morality of Opacity, Lies and Deceit

Kant was an absolutist

Regarding lies and deceit,[1] there are two basic choices. A person, group, party, political leader and anyone else can play their cards close, or semi-close, with blunt honesty when it is called for. Given the human condition, some things need to be left unsaid, e.g., because truth causes more harm than good. It's usually, or more likely almost always, not only black and white. Some harm and some good are both there. The issue is how one sees the balance. Opinions will differ. 

I have a powerful personal bias against unwarranted opacity in politics, including truth withholding for the alleged benefit of me, anyone else, any group, the nation or society. IMO, opacity is where (i) crime and corruption, (ii) authoritarianism, (iii) social and personal abuse, (iv) incompetence and (v) contempt for truth and the rule of law hide and flourish. Lies and deceit of omission are no more moral or justifiable than lies or deceit of commission. 

Re authoritarianism: I now firmly believe it is an absolute necessity for the rise of out-of-power demagogues to the status of tyrant or kleptocrat. If there are exceptions to that personal rule, I am unaware of them. Hate of unwarranted opacity has long been my bias. On the matter of lying and deceit, I am persuaded by the reasoning of moral philosopher Sissela Bok, who brilliantly capsulized the issue for democracies: 

“[Johnson repeatedly told the American people] ‘the first responsibility, the only real issue in this campaign, the only thing you ought to be concerned about at all, is: Who can best keep the peace?’ The stratagem succeeded; the election was won; the war escalated. .... President Johnson thus denied the electorate of any chance to give or refuse consent to the escalation of the war in Vietnam. Believing they had voted for the candidate of peace, American citizens were, within months, deeply embroiled in one of the cruelest wars in their history. Deception of this kind strikes at the very essence of democratic government. 

When political representatives or entire governments arrogate to themselves the right to lie, they take power from the public that would not have been given up voluntarily. .... But such cases [that justify lying] are so rare that they hardly exist for practical purposes. .... The consequences of spreading deception, alienation and lack of trust could not have been documented for us more concretely than they have in the past decades. We have had a very vivid illustration of how lies undermine our political system. .... Those in government and other positions of trust should be held to the highest standards. Their lies are not ennobled by their positions; quite the contrary. .... only those deceptive practices which can be openly debated and consented to in advance are justifiable in a democracy.” 

If that reasoning is good for a national government and democracy, why isn't it good for a political party or a person? IMO, the logic flows like water just about everywhere, including to deceptive demagogues and tyrants. Or is that reasoning flawed or wrong?

Footnote: 

1. My definition of deceit includes unwarranted emotional manipulation, which usually arises when irrational or unwarranted fear, anger, hate, distrust, bigotry, etc., are fomented by speech or behavior. That's usually done intentionally to divide people and dehumanize allegedly threatening people or groups. Deceit also includes application of motivated reasoning to facts and truths (especially inconvenient ones) to distort real reality into a false reality. In my opinion, lies, unwarranted emotional manipulation and motivated reasoning are all forms of deceit.

Motivated reasoning: a cognitive biology phenomenon where personal biased reasoning produces justifications or make decisions that are most desired rather than those that accurately reflect the evidence and/or unbiased reasoning; it is an evolved personal defense mechanism against cognitive dissonance that arises when personal beliefs or desires conflict with reality or reason-logic; it is a tendency to find arguments in favor of conclusions a person, group or tribe wants to believe despite contrary evidence and/or less biased reasoning that would lead to a different conclusion or belief