He never said never use any risk mitigation, but that the risk mitigation in this case seems excessive for the risk involved. Fires are rare, and in the case of the NYSE, the fire in the data center affected only one pod, and was quickly extinguished,. They all are.
The problem with fire isn't the fire, it's that the fire triggers automatic responses (disconnecting the power), and the room is sealed while the fire is investigated, before the power can be turned back on. So the "fire" almost never does damage beyond the system it started in, but will almost always take out a data center for a day.