They're talking about something the size of a boulder according to TFA. Earth gets hit by objects this size all the time.
The diameter of the biggest impactor to hit Earth on any given day is likely to be about 40 centimeters, in a given year about 4 meters, and in a given century about 20 meters.
https://en.wikipedia.org/wiki/Meteoroid#Frequency_of_large_meteoroid_collisions_with_Earth
"There are other elements involved, but if size were the only factor, we'd be looking for an asteroid smaller than about 40 feet (12 meters) across," said Paul Chodas, a senior scientist in the Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory
To do nothing is to be nothing.