You have to take in count that those people you're trying to judge for excessive IC violence are actually mostly teenagers in real life, most of them live in middle-class neighborhoods where they have never stumbled across a street gangster and almost everything they know about street gangs/OCGs and their lifestyle is just based on a bunch of Wikipedia articles, Google documents and a couple of Youtube videos, which were posted by News agencies that love to amplify things for views.
It's basically what they've been seeing and reading throughout their research into whatever organized crime group or street gang they are trying to portray, whenever you read an article or a news report about a certain gang they just try to make it look like as if we're living in Idlib, Syria where everyone is shooting each other and the whole city is a warzone, which is way too far from reality. You see factions dropping bodies on the daily as if they're in Afghanistan thinking it's real because they got a reason for doing it in-character but that's not how it goes in real life, because if you commit a single murder in real life you are gonna get got, authorities are eventually going to arrest you and the possibilities you're gonna end up in a Federal prison with a needle in your arm are high, that's why it's a big risk to just kill someone in real life even if you're a badass mobster you're going to think hundred times before doing such an act, that's why mob hits rarely happen nowadays because the law isn't so tolerant as it used to be, and with the advancement of technology the chances of you getting away with the murder are so mild, and detectives don't get bored in real life because that's their job, they're gonna chase you until they put your hands in cuffs even if it takes them decades.
If you compare that with how it is in-game you will know why illegal role-players don't really care much about committing excessive violence, first of all there's nothing serious to worry about because what's the worst that's gonna happen? You can CK me, not that much of a big deal. Cops found the body? Bruh, just lay low for a couple of hours and they will forget about it as they get busy with other in-character incidents that are more interesting, and if you wanna save yourself the headache just take them somewhere in the county and finish them off, it's not like in real life where there are tenths of thousands of people living in county outside the city as they're scattered all over the place, which gives high chances for someone to discover the dead body of that person you've killed.
The reason I said all of this because I wanna reach a point, and my point is that videogames are gonna stay videogames and even if they were meant to simulate real life, it can never be ideal, it will stay somehow far from reality and less detailed than how real life is, no matter how hard you try to change that fact it's simply not gonna change.