Hiroshima exploded 67 terajoules of energy i.e. $6.7\times 10^{13}$ joules. We may calculate the mass of the Russian meteor assuming that the speed is $v=20,000$ m/s:
$$ \frac{1}{2} mv^2 = 6.7 \times 10^{13} $$
We obtain 335 tons. The numbers aren't precise but they're in the ballpark and reasonable. The Russian academy of sciences actually estimates 10,000 tons which would be something like 700 Hiroshimas.
The Hiroshima bomb was harmful because its energy was focused on a small place, several kilometers around the explosion were destroyed. The energy of the Russian meteor was distributed to a much larger area of radius closer to dozens if not 100 km and much of the energy was deposited to the atmosphere, so the local impact was significantly smaller than it was in Hiroshima. If we exaggerate a bit, the energy was spread to 20 times longer distances than in Hiroshima and the dilution scales as something in between the second and third power, so one gets about 500 times smaller "local impact" at the relevant places than in Hiroshima even if we add the factor of 30 (30 Hiroshimas).
Some individual collisions detected on the ground were estimated to have just 1 TJ or so, 67 times weaker than the Hiroshima. The bulk of the energy was deposited to the atmosphere.
But I guess that the main reason why you find the numbers counterintuitive is the widespread antiwar propaganda that prefers to present a nuclear blast as a nearly supernatural event of nearly infinite proportions. This ain't the case. The bomb in Hiroshima was just another bomb, a bit stronger one (plus some annoying radioactive stuff that had other consequences, something that wasn't caused by the meteorite). Five kilometers from the ground zero, they experienced similar symptoms as they did in Chelyabinsk – broken windows and a reasonable but not infinite sound of the explosion. Hundreds of meters from the explosion, things vaporized and the Russian meteor had no place with this much concentrated energy.
