You haven't answered the basic question
For a long time, people like you and EP have been claiming that this particular comet caused huge impacts DIRECTLY through a firestorm, and that therefore we should be running around like Chicken Little because "the sky is falling".
Now, that evidence has been questioned and all of a sudden you're telling us that the mammoths were put off their feed by noises in the night?
Far more likely, human and other "impacts" on the environment caused a steady decline of large meat animals.
Now, what does this all say about the risk from NEO's and cometary impactors?