https://www.pcgamer.com/cyberpunk-2077-will-let-you-fight-most-people-but-not-kids-or-story-npcs/
 
Cyberpunk 2077's Night City is full of people for you to beat up, including gang members, cops and corporate douchebags—there are limits, though, so you won't be brawling with everyone. Children, for instance, will be protected from your murderous rages, along with story-important NPCs. 
 
Personally I think it's good to have rules like this. 

I think it should be a toggle for children who are not part of the main storyline but have a very harsh punishment for players who go that way. Like all cybernetics stop working and the police come for you. Of course if you could hurt random kids it probably would be some accident that would cause the punishment like an explosion or car crash that does it and the player would be punished for something they didn't mean to do.

blackforce
Kill everyone children, women, dogs, cats why  just men? why not it's a dammn game.
why is it ok to at all if that's the case.

I can understand the reason since it used to be open world games didn't really have kids so everyone could be a target. Of course if you don't allow something in a game it's the thing people will notice and want to do it. I kind of feel the best way to deal with it is stiff punishments for the player so they wouldn't want to but of course the ratings board might have something to do with it also since they could just rate the game AO and it won't sell at that point until they bring it down to M.