You can literally turn on chat filter so why do you report bad words
explain the logic to turn off chat filter and then get upset when somebody says a no no
As others have said, swearing is not in and of itself against the rules; it's leveling swears at another player that crosses a line. It's the difference between saying "aw, fuck" and "go fuck yourself you piece of shit".
Additionally; the Mature Language Filter is simply there so that people with sensibilities to swearing/harsh language don't have to see it.
EDIT: So chat filter is basically a band aid to what people say so muting should be the solution or continue to get emotional on a game and report people.
Muting is a solution, but it's also a band-aid solution. It only prevents you from seeing further chat misbehavior; it doesn't magically stop someone from flaming and being a general ass. Another solution, one more likely to actually rectify the toxic player's behavior, is to report them. More often than not, a punishment is a surefire way to get players to shape up their behavior.
And, no, not every report is emotionally charged. It's more appropriate to say that the people getting toxic are the ones who get emotional than the ones who report them; after all, who's the one ranting and raving in chat, and who's the one quietly giving Riot the heads-up that someone's acting out?
And, of course, it has to be said; The mute feature doesn't supercede the rules you agreed to upon signing up for League. You agreed to a set of rules; if you decide to break them, you don't get to complain when you get punished.