In the West, "strong language" (e.g. lots of cussing) will net you a higher rating (e.g. rated M) or even get videos on YouTube demonitized. Is there essentially no such concept in Japan? To be clear, I am excluding "adult themes" and "explicit content" (e.g. talking about sex). To my knowledge, Japanese doesn't really have "cussing", but rather "rude speech". Would talking in a rude enough manner really bump up the rating of something, similar to "Strong Language" in the West? Or is that essentially not a concern in Japan?
CERO, the Japanese game rating organization, has the following in its regulation regarding what are banned expressions (禁止表現):
Games that contain such words are subject to "no rating" (i.e., ban of sale) rather than just an increase of rating, so it's a real concern at least on the rules.
That said, I don't know why, but I have a feeling that Japanese people (even outlaws and hip-hop musicians) tend not to use dirty words in their sentences. In foreign games, I sometimes see characters who use words like these in rapid succession and a large part of their conversations is bleeped, but I cannot imagine a similar way of speaking in Japanese. Many game developers have complained that CERO's regulation of violence and sexual content is too strict, but I have never heard of a similar issue with respect to "simply dirty words".