>You really don't see any other way to word that same sentiment?

The problem with being polite is that the other too easily mistakes the politeness itself for encouragement, even if the comment is entirely negative. Generally ridicule is a good way to get someone to stop, as it makes very clear what you think and discourages continuing. Of course name calling is too easily dismissed and can easily lead to defiance. As discussed before, any kind of politeness is easily ignored or mistaken as positivity.