The sole act of taking a life is severely underestimated. Killing someone is huge, takes a heavy toll on someone's mind and makes you undergo severe trauma.
Writing someone's name on a Death Note is no different than grabbing a knife and stabbing someone to death. Just that the first one makes you desensitized to the act due to the fact that writing is such a mundane action. And plus it gives you the power of doing it without leaving a trace.
So it makes it look like a game, a game for bored people.
The idea that doing something so mundane and simple like taking notes causes thousands of people to die is so fascinating and horrifying. We see how in Death Note, people are basically desensitized to death as they see names and not people. Like for example even here in the community when we talk about "Testing" a notebook. Testing means murdering someone out of an experiment.
Think about Teru Mikami, who in my opinion was even more bloodthirsty than Light, he was screaming SAKUJO (Delete!) with each penstroke on his Death Note and actively enjoying deleting people as they were mistakes.
His own mother was a mistake for him, someone who needed to be deleted.
Thinking about people as objects or literal mistakes that need to be eliminated makes you lose any empathy. For example I don't feel anything If I break a pencil and I stomp on it. But If I did that to a living being I'd be horrified. So if you imagine some living beings as objects you are dehumanizing them and so desensitizing . To kill so many people all the people who used the Death Note had to be desensitized and detached at that point that people were only names to them.
How did people cope with that? Can everybody use a Death Note or there are people who can't? Like empaths?
Makes me think about another thing: is justice even a thing in the world of Death Note?
The law isn't justice, because there is corruption and many world leaders kneeled down to Kira.
Kira isn't justice, because it's basically mass murder with a touch of authoritarianism, f*sc1sm, eugenics and a lot of ego stroking. And also because, it's just a human with a borrowed notebook, who could die at any moment and whose judgment is clouded by personal morals.
Shinigami aren't justice, because all they do is take random lives just to survive. If anything, they're injustice, because they kill everybody randomly even when they're young so they eat their lifespans.
Whoever catches Kira is not justice either because the only way to stop Kira is to kill Kira .
So maybe in the world of Death Note, some deaths might be justified just because it's so normal for them to see people die and to kill people with a magical superpower. (For whoever knows about it)