There were 18 Bengal tigers shot in the Ohio incident. This is not 7% of the captive 'bengal' tiger population in the U.S. alone. There are more 'bengal' tigers in captivity in the U.S. than there is in the wild and the last estimate I was told on bengals was a wild population of 1,500-2,000. The facility I work at has 10 bengals alone not including other subspecies of tiger. There are many people who doubt the purity of 'bengals' and ensure the only pure bengals are found in India alone, as many 'bengals' in facilities are hybrids between either Sumatran's or Siberians.
Also saying the above, the facility responsible for the Ohio incident was not an accredited facility as far as I'm aware so even without the origin of captive bengals in doubt I would say it was highly probable his 'bengals' were from poor genetics anyway.