This is some turnstile justice.
A repeat offender was free to punch a 37-year-old pregnant woman in the face on a Queens subway train last month after he committed three other similar transit attacks in the past four months — but got repeatedly let back out to do more violence, sources said.
Christopher Benitez, 33, of Brooklyn – who has 16 prior arrests – was busted again Friday for slugging his latest victim on board a J train at the Jamaica Center-Parsons-Archer station around 5:50 p.m. Feb. 25, according to cops and sources…