Answer: Because humans, especially in peacetime, and especially, modern comfortable humans, don’t have much experience with the deaths of many younger people around them, and get especially preoccupied with human deaths near them, the possibility of their own death, etc.
(The main irony to me is about the relative lack of attention given to the apparent threat from the human-caused Worldwide Extinction Crisis and Climate Change crisis, which threaten to kill perhaps all humans.)
But also, the points made by others above about how COVID is not through killing people, and that it’s in spite of our best efforts, are very well-taken. Also the impact is not just deaths it causes but others who die from side-effects of the impact on health care systems, and the people with lasting or permanent effects of the disease who are still alive, and the other impacts on everyone of the response to the disease, etc. Reducing it to the percent fraction of total world humans so far, is a very reductive statistic to look at.
Here are some quick relative statistics from other well-known historical human death events, which might be interesting to compare:
Black Plague (1347 – 1351) deaths: estimated 25,000,000 – 50,000,000 (~30–60% of European population)
The Seven Years War (1748 – 1756) deaths: estimated over 850,000 (~0.73% of European population)
US Civil War (1861 – 1865) deaths: about 750,000 (2.5% US population)
World War I deaths: 20,000,000 (1.12% world population), (and 21,000,000 wounded) (United States deaths: 418,500 (~0.4%))
Flu (H1N1) pandemic of 1918 deaths: at least 50,000,000. (2.7% world population)
World War II deaths: about 70,000,000 to 85,000,000 (3.0 to 3.7%), (US deaths 419,400, 0.32%)
9/11 deaths: 2,977 – some people maintain “the world changed forever”, we need security theater, etc
“WaR on tErRoR” deaths: estimated 897,000 to 929,000
Bird flu (H5N1 2003–2007) deaths: 349 (declared a pandemic by US CDC)
Swine flu ((H1N1) 2009–2010 pandemic) deaths: estimated 284,000 (18,449 lab-confirmed) News media was also saying the world changed forever about this.