Earlier quoted context omitted.
Yes, we are primed as animals that we are to be scared and vigilant. Because that ensured survival.
I watched a farewell video of a very far right person dying of Covid. He didn't get vaccinated but I don't know if it was because he was anti-vax, didn't think Covid was real or didn't get a chance as this was early in the pandemic. It was a recording made from a hospital bed and uploaded to Facebook. As he was saying his goodbyes he said something like "...and tell Brandon (son) I love him, not to trust anyone, and…
But more seriously, the reason people indoctrinate isn't because they want them to be negative, but to realize that being pessimistic is actually going to be a more reliable way to have a plan for life when no one is able to help.
For example, if your car breaks down and your cell phone battery is around 30%- you have time to make a few phone calls, but instead of wondering if your friend can pick you up (assuming he has a cheap pickup truck that can tow), you rationalize- he might be sleeping, working, unwilling to answer the phone. You have three phone calls to make, so you decide you'll compare the rates of the two nearest towing companies.
Which do you call? You have money and time to spend, but you don't want to be stranded for a very long time, even assuming you were able to pull your car over to the side of the curb. Being pessimistic is just being prepared, and similarly, you want to try to save for a rainy day.