We have to remember that although in this situation the end of the runway is mud and therefore no serious damage occurred to the a/c or pax. My local airport has the sea at the end of the runway, this would have been rather more serious.
So don't just look at the actual outcome(muddy nose-gear), think also of the potential outcome(broken fuselage/pax injuries/open seawater) - then decide if it is a serious event or not. Open your eyes a little people!