And by being rude you help preventing it? Quite the opposite, the way I see it... ;-)
While appreciating your concern, I think the moderators can deal with time wasters quite adequately, and without rudeness.
This goes beyond just the ESL forum. It is all very well for you and everyone else to take the soft approach, which experience in every day life shows has no impact on the continuing downward slope in our society. We face a continuing threat to the way in which all of us are treated; it is not a simple matter of each of us taking action to ensure that each of us is treated with respect. Respect within our society has declined with a growing number of the population not even knowing what respect means. The way in which they are made to think is by bringing them up short, making them think. Being nice to everyone regardless of what they do or say has had no impact. Thirty years ago it was obvious that the lack of discipline in our schools had already lead to serious problems, within and without schools. Complete failure to have any idea of what respect for others means, and to even be bothered about others is a follow on to the liberal society which we now have where rules do not exist any more. For those who think that they can do anything that they like, the only way forward is to challenge them. It does no good to let them carry on regardless.