There need to he clear rules. If we shut down every forum where someone says something bad once, are we going to shut down Facebook and Instagram? Of course not, we'll stop short of that. So we give an unfair advantage to Facebook and Instagram, forever entrenching them as the only platforms where speech can happen?
Getting back to the Princess Diana analogy, KF probably started as a harmless place to joke about public figures, but in the modern world where everyone is pushed to cultivate their own personal "brand", even someone as uninteresting as a nintendo emulator programmer, it puts regular people at risk of the worst kinds of stalking and harassment etc.