Well, here's a quote from your link that shows that governor Cuomo didn't veto it because he was in favor of putting innocent people behind bars. He actually just wanted the law to be even more clear:
"In response to the Governor’s objections to last year’s bill, this year’s bill removes “centrifugal force” from the definition of a gravity knife and adds “solely” to create a bright-line definition that even overzealous New York City law enforcement and prosecutors can understand, as desired by the Governor. It would preclude the unconstitutionally vague “wrist flick” test that has resulted in over 60,000 arrests and prosecutions in New York City which the Governor himself described as “absurd” in vetoing last year’s bill on New Year’s Eve."
"In response to the Governor’s objections to last year’s bill, this year’s bill removes “centrifugal force” from the definition of a gravity knife and adds “solely” to create a bright-line definition that even overzealous New York City law enforcement and prosecutors can understand, as desired by the Governor. It would preclude the unconstitutionally vague “wrist flick” test that has resulted in over 60,000 arrests and prosecutions in New York City which the Governor himself described as “absurd” in vetoing last year’s bill on New Year’s Eve."