So, why isn't this a thing yet?

[DasFelix]

And the game is rated R18+ because of that in Australia (if we didn't have that rating for games, it would either have been banned or heavily censored... or it is censored somewhere). A child dying from sickness or some other means (that is not graphically violent in one way or another) wouldn't affect the rating much, but a child being physically harmed, or even killed, would boost the games rating to MA, R or banned.

I looked about and see that Metal Gear Solid V has been censored in certain countries. So there you go.

I'm pretty sure the R-18 Rating in Australia is very recent too so it's a good argument.
Before that we had quite many Games that couldn't release over there because of that.

On a side not the parts of MGSV that where censored where the Torture Scenes, not the Child Soldier part.