Lets ban the Subway Trains. After all that was the actual mechanical device that caused the fatal injuries. It should be obvious that since there have been two people deliberately murdered by homicidal maniacs in the last 6 months that it is the Subway Trains that are inherently unsafe.
You can't keep ~crazy people~ from killing other people unless you are willing to isolate the crazies from society. Since the 1960s the ACLU and other touch feely groups, whose chief hallmark is a lack of common sense, have been working to put as many crazy people as possible in contact with the general public on a daily basis.
The net result is that we have reached the situation where the asylums are empty and the crazy people are running amok.