If you listen to his detractors, Jeremy Corbyn is a monster who will divide and weaken the party, possibly even destroy it, and this is true but then again it's not true at all. In fact, these nightmarish forecasts are nothing more than hysterical guff with no weight behind them and this is why we must take them seriously.
The vultures have circled around Labour for years. Miliband even showed off a giant gravestone at one point, and outsiders have frequently dealt the party a huge blow, e.g. Russell Brand, who displayed a sudden passion for politics and urged his apathetic fans to vote for Miliband... a mere 14 days after the deadline to register had passed!