Putting it unkindly, it's easy enough to be sarcastic and refer to him as our Liar-in-Chief.
I'd like to point to a paragraph from the article you posted and compare it with observations noted in the article I posted, which were based on NY Times interviews with "60 advisers, associates, friends and members of Congress."
Regarding his propensity for "unkind lies", from the article you posted:
"The most stunning way Trump’s lies differed from our participants’, though, was in their cruelty. An astonishing 50 percent of Trump’s lies were hurtful or disparaging. For example, he proclaimed that John Brennan, James Clapper and James Comey, all career intelligence or law enforcement officials, were “
political hacks.” He
said that “the Sloppy Michael Moore Show on Broadway was a TOTAL BOMB and was forced to close.” Talking about green card applicants, he
insisted that other “countries, they don’t put their finest in the lottery system. They put people probably in many cases that they don’t want.” And he claimed
that “Ralph Northam, who is running for Governor of Virginia, is fighting for the violent MS-13 killer gangs & sanctuary cities.”
The Trump lies that could not be coded into just one category were typically told both to belittle others and enhance himself.
For example: “Senator Bob Corker ‘begged’ me to endorse him for reelection in Tennessee. I said ‘NO’ and he dropped out (said he could not win without my endorsement).”
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Now, consider the view he has of his office, and the situation he finds himself in as President, and as described by the Times article I posted:
"As he ends his first year in office, Mr. Trump is redefining what it means to be president. He sees the highest office in the land much as he did the night of his stunning victory over
Hillary Clinton — as a prize he must fight to protect every waking moment, and Twitter is his Excalibur. Despite all his bluster, he views himself less as a titan dominating the world stage than a maligned outsider engaged in a struggle to be taken seriously, according to interviews with 60 advisers, associates, friends and members of Congress
For other presidents, every day is a test of how to lead a country, not just a faction, balancing competing interests. For Mr. Trump, every day is an hour-by-hour battle for self-preservation. He still relitigates last year’s election, convinced that the investigation by Robert S. Mueller III, the special counsel, into
Russia’s interference is a plot to delegitimize him.
Color-coded maps highlighting the counties he won were hung on the White House walls.
Before taking office, Mr. Trump told top aides to think of each presidential day as an
episode in a television show in which he vanquishes rivals. People close to him estimate that Mr. Trump spends at least four hours a day, and sometimes as much as twice that, in front of a television, sometimes with the volume muted, marinating in the no-holds-barred wars of cable news and eager to fire back."
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"Before taking office, Mr. Trump told top aides to think of each presidential day as an
episode in a television show in which he vanquishes rivals".
I suggest, that since he sees every day as a battle to protect himself and his position, he takes every opportunity to slam those he perceives as his enemies, and thus we see him telling far more "unkind lies" then might otherwise be the case. He's in a prizefight every day he sits in that office. He slams his "enemies", including our 4th estate, our press, the watchdogs of our democracy, and indeed telling lies about them is only natural from his perspective. The fact that some in that free press have been quite sloppy with the facts of late certainly does not help, and helps him in this daily war against anyone who opposes him.
Further, creating a totally fake reality is a part of his path to vanquishing his enemy, and maintains the support of his base. It's basic: tell a lie often enough, and people begin to believe that lie. Hence we find ourselves in the situation that exists today: a fake reality or fake narrative that butts up against the truth of the matter all the time, and which is helping create a situation where a % of the American public are fully committed to that fake narrative, believe in it 100%, and are unwavering in believing their President is actually telling the truth with his lies, and is under attack by "the lying media".
Those who have eyes to see can readily see what's going on here, and our understandably concerned by his tactics, since it is clearly damaging to our democracy to help create a fake narrative/reality that will continue to exist after he has left that office. It's the whole problem of the so-called Post Truth era that nobody more then Donald Trump and his propaganda organs, like Fox News, are helping to establish as the norm in the United States. When we get to the point where facts vs. alternative facts(thanks Kelly Conway!) is the daily fare, we are in deep trouble.