Lots of US people here work in places where these two non-pruriently-posed cartoon nudes, used for a valid illustrative purpose, present no 'safety' problem.
Please don't make the US work environment seem more prude or homogenous than it actually is. This is not "definitely, most very not-safe-for-work". It depends on where you work. That makes "mildly NSFW" a fair description - it's enough of a warning for those in very sensitive environments, while allowing that in other places it'd be considered harmless.