It's not "derangement", it's called politics. The other party always tries to establish an unflattering narrative about the other side. Kerry was a doe eyed hippy turned new england aristocrat who would try to fight terrorism with doves and posies. Obama was an inexperienced rockstar masquerading as a qualified candidate. Romney was a Mormon version of Mr. Burns and took sick pleasure in laying people off by the thousand.
None of these descriptions are balanced or accurate description of any of those candidates. But there was at least some marginal aspect of that narrative in things that people could point to. John Kerry did throw his medals at war protests and was a rich New Englander. Romney's Bain days did often involve laying off lots of people. Obama's resume was kind of slim.
Clinton's experience and qualifications are pretty much beyond reproach, and she's far too disciplined a politician to make a habit of saying things that could make her look out of the mainstream. So those aren't effective areas to attack her. So But it so happens that quite lot of people feel that Clinton is dishonest. Any time there's something that you can point to that reinforces the perception that Clinton is dishonest, it will be pointed to. Because it's politics and that's what you do in politics.
Every week Trump does or says something which reinforces the perception that he is a wackjob. And every time he says one of these things, Democratics bring it up over and over for multiple news cycles. Do you think they're doing that because they are deranged? Of course not. This is how politics work. You don't attack your opponent by writing a fair minded and thoughtful 2,000 word essay making the comprehensive case that they shouldn't be elected. You find a simplistic one sentence caricature that resonates with people that can be repeated ad nauseum.
Every time George W. Bush spoke an incomplete sentence or stammered for half a second, video of it made the rounds and everyone laughed at him for being stupid. But guess what - everyone speaks in incomplete sentences, mispronounces the occasional word, and stammers sometimes. So why did we all pick on Bush for it? Because lots of people already thought he was dumb, and once there's an existing narrative about someone, anything that reinforces it - even really minor things - get lots of attention.
With Hillary Clinton, that narrative is dishonesty. 90+ percent of all voters are low information voters, so when you're going negative, smart political messaging is not about presenting facts in a logical manner to steer voters toward an unfavorable opinion of your opponent. It's about determining what negative feelings people already have about your opponent, and then relentlessly reinforcing those negative feelings.
It's hilarious to me how so many people react to broad partisan political messaging by thinking that there's some ulterior motive. Both sides are just trying to win the election. "The Republicans are deranged and have a psychotic hatred of Clinton!" "The Democrats hate freedom and want to purge our society of [guns/christianity/whites/my right to develop type 2 diabetes before age 25 - ]"
Both sides are just trying to win. They aren't deranged or obsessed with anything. They are just harping on the same basic point over and over and over because they believe that voters are too stupid retain more than that, and for the most part, they are correct.