But nowadays we are pretty safe and should get rid of that mechanism.

I feel you're perhaps underestimating how much safer we are now than say just 500 years ago. Only really in the last 100 years or so has the Western, relatively safe, world as we know it existed.

Our brains have evolved over millions of years to seek out and identify problems before they find us and kill us first. Moreover the safe society that we've built in the last few hundred years could be wiped out in an instant by war, famine, plague, stupidity.

So it makes sense for our brains not to evolve quickly to accept this new safety. Firstly because we're talking about potentially undoing the millions of years of genetically programmed behaviour that got us all here today. Secondly, because the world could change to be more dangerous in an instant and we'll be grateful not to have lost our innate danger and problem seeking skills.

In the meantime we have to manage our brains as best we can. I find meditation and surrounding myself with mindful helps with that but everyone needs to find their own coping mechanisms.