With the profanity filter turned off, you will see exactly what other players type in their chat, warts and all. Note that, as you have made a concious choice to turn off your profanity filter, you should not report other players simply for using the odd bit of bad language. You can and should still report other players who are being discriminatory, bullying, threatening, lewd, salacious, soliciting, etc, regardless of whether or not they are using bad language! It may be worth familiarising yourself with our rules on innapropriate language and behaviour, but, basically, so long as you are responsible and respectful to other players, you have nothing to worry about.
As Bladewing has quoted, if you find something offensive then report it. Jagex will make the final decision as to whether somebody will be muted and the severity of the insult. We all find different things insulting, which is why there is no one defining rule as to what is and isn't offensive. So just report what you find offensive and leave it at that.
For this topic, it has become a flamefest at the OP therefore I am locking it.