I think a line has to be drawn, based not on the subjective magnitude of the hurt, but on the appropriate recourse. In civilization, if attacked with sticks & stones, we are expected to take recourse, not to bigger sticks & stones, but to government, which is supposed to keep the peace by quelling cycles of revenge. With words, however nasty, we are reasonably expected to retaliate (if retaliation is called for) with our own words, and not go crying to the police (or teacher). Bullied people should band together and practice giving shit.