I really strongly disagree with using this as a guiding principal, it just opens up a huge amount of inconsistency and unfairness.
What if the supporter demographics change from all adult to mixed adults/kids half way through the game - are you suddenly sending a player off for language which has been acceptable for the first half? Or vice-versa - send a player off for OFFINABUS, then later in the match there are no kids around so you can just let the same language go? What if you set this up as your philosophy, but fail to notice a kid joining or leaving the spectators mid-match, and therefore apply the wrong morality standards in any given moment?
Similarly, I don't think it's reasonable to expect the away team to have scouted the area and adjusted their language in response. You as a referee are of course entitled to set the bar where you see fit and need to be prepared to explain and act on that as necessary. But there are enough on-pitch factors that you need to be able to react to in order to set your tolerance, adding geography/crowd demographics/weather/..... is just going to cause you to misapply your own standards.
I hate to be the person who moans about NIMBYs, but if you have a problem with swearing then you need to be smart enough to factor in the existence of a sports field when buying your house. If I buy a house with a garden backing onto a football pitch, I know to expect 2 things: lots of shouting on Sat afternoon/Sunday morning, and occasionally I will find a free football in my garden!