A virus is like any other organism, it wants to live, and reproduce. By nature, it does not want to kill the host as that is counterproductive to its most basic evolutionary instincts- it's own survival, and reproduction. That's why they naturally mutate into less lethal organisms.
Well... how do viruses become lethal to begin with? Surely they mutate sometimes more lethal and sometimes less lethal?
If there is a Delta Variant is was 100% made in a Chinese lab though.
A virus is like any other organism, it wants to live, and reproduce. By nature, it does not want to kill the host as that is counterproductive to its most basic evolutionary instincts- it's own survival, and reproduction. That's why they naturally mutate into less lethal organisms.