An irate subway rider pummeled a man who bumped into him on a Brooklyn train late last month, cops said Wednesday.
The 36-year-old victim was onboard a northbound J train stopped at the Kosciuszko Street station in Bushwick around 1 p.m. on May 21 when he inadvertently knocked into a stranger, police said.
Rather than letting it go, the seething straphanger demanded an apology from the bumper, cops said…