See, the thing is, its only bad in YOUR opinion. Not everyone minds. Also, your entire arguement is based on the fact that YOU think it is a sin, but there are many people who either don't believe it is a sin or don't believe in God. Its dangerous to base laws on religion, as religion is only a matter of opinion. I wish it was against the law for people to become so religious that they are blind to common sense...but thats just my opinion and soits silly to expect a law to be made on it. I cannot emphasise this enough: Religion should not influence the law. It's quite simple really - if you think it's wrong to swear, don't do it! But why does that mean you can force your opinions on everyone else?
I'm not entirely sure what you're asking, as your question is actually a statement, but I'd like to add that I am appalled that someone can say that people who swear are weak or selfish. To me, comments like that just show how badly religion had twisted some people's thoughts. Swearing has absolutely nothing to do with being weak or selfish and its ridiculous for anyone to even suggest that it is.
I have two points to finish with. Firstly, this law would be impossible to enforce. Secondly, FREEDOM OF SPEECH.