Where to begin? Let me start with some reasoning, before proceeding on to the Ad Hominem part. Let me know which you are

There is a logical fallacy called the base rate fallacy, that says that when dealing with a specific case, you also have to look at the base rate. That involves lots of math, so I will just refer to it by another term: the waving a metal pole during a lightning storm fallacy or the I am going to smear myself with salmon and wander around in bear territory fallacy. Do you know how many people die from lightning strikes each year in the United States? Apparently around four. Do you know how many people die from bear attacks in the United States each year? Usually one or two. So we are talking about a 1 in 100,000,000 chance of death by lightning and/or bear. So, the clever person might think, what harm is there in you know, taking a metal pole outside and waving it around in the middle of a thunderstorm? What would be the problem, this very clever person might ask, in smearing myself in raw salmon and wandering around in the mountains in Montana in October?

The obvious answer is that statistics don't tell an entire story, especially when we can pretty clearly see logical chains of cause and effect. The things that people are afraid or upset about concerning what Trump might do are things that are totally backed up by evidence of things that he has very publicly said and did recently. If a politician publicly comments about what a political rival would when you put a gun in their face, it makes it more likely that they would actually do this thing. Does a president want to be a dictator? Well, if a president praises Hitler, it really increases the fact that that isn't just a hyperbolic statement. And the person who made the revelation that Trump wished he had "Hitler's generals" was John Kelly, his former Chief of Staff, and someone who was generally politically supportive of Trump's agenda. Until he worked for him. This did not come from a hysterical tumblrite, this came from a four star general. Is it an exaggeration to say a politician is planning a coup when he has already tried to do exactly that, and was willing to send a mob to threaten or kill even his own vice-president? You can argue about exactly what Trump wanted to happen that day, but he has never apologized for what happened or said it was wrong.

The one thing that has to be mentioned is that personally, I think the signs of Trump's gathering dementia are perhaps a bigger problem. I am not a doctor, but I know when a 78 year old man starts miming oral sex on a microphone in public, that there might be some impulse control problems. Is this dementia or just something else? I can consult basic statistical guidelines:

"Rates of dementia and mild cognitive impairment rose sharply with age: three percent of people between 65 and 69 had dementia, rising to 35% for people aged 90 and over."1
So anyone who wants to do the integral calculus can tell us just what percentage chance a 78 year old man who has been spacing out in public might be suffering from dementia. Does a man with poor impulse control having access to enough nuclear weapons to destroy human civilization make you nervous? If so, it might be for reasons other than spending too much time online.

The people who are worried about Donald Trump's autocratic tendency and erratic behavior are not pearl clutchers or hand wringers. And you, Hazelnut, are not a big clever boy who is above it all and sees things more clearly than us.

Okay, yes, now it is ad hominem time. But I will keep these mild. Because the above is at least entertaining. But also, pretty mediocre. As far as I know, Hazelnut is British, and I don't know if he has visited the United States, and which parts, and for how long. (I actually asked him this information, but haven't got an answer, if I am wrong, I will update this). But I have lived in the United States for most of my life, and I have visited 44 states, and lived in five. Most recently, I lived in a small town in Montana. I have seen the United States from San Francisco to some of the most remote towns in the United States. And most of the stereotypes presented above about the people scared of Trump are...well, they are lazy stereotypes about how "screen addled" "reddit users" make fun of people in "flyover states". It is lazy stereotyping of people's lazy stereotyping, which gets points for being "meta", but there is nothing in the above writeup that shows any insight or experience into what people in the United States are like. Someone is criticizing people for being "terminally online"...but seems to have formed their opinions through second or third hand social media experiences. "Ah, I saw someone else caricaturize Bay Area liberals on the intarwebs! I am not an expert in all of American politics and society!" Sorry, nope, that doesn't work for me.

Anyway, there are one or two good ideas above, but to sum up: the people who are worried about Trump have very good reasons to be worried, based on Trump's public words and behavior. And the people who are worried about Trump are not some stereotype of hysterical tumblr users, but are a wide cross-section of American society.