We've just debated bad language here recently:

https://forums.totalwar.org/vb/showthread.php?t=72623

A couple of things I would add that are specific to the original poster's complaint.

First, the context and usage of bad language is important. If Hugh Grant swears two dozen times in the first few minutes of a light comedy film, it is less offensive than if a big pugnacious drunk approaches you threateningly and swears once in your face. I typically edit out swearwords that are used in a fairly innocent way (e.g. drat! (substitute swear word of choice) I hit my thumb with a hammer!) without bothering the poster. But where they are used to insult or attack, that's a different matter.

Second, moderators may are likely to treat repeat offenders more strictly. With a first offender, I may raise the issue by PM or give a zero point warning. With a persistent offender, I am likely to start giving warning points.

But again - it's not rocket science. It ultimately boils down to this:

Forum rules = no swearing.

Breaking forum rules = warning.