For reference, a "gravity knife" is something originally issued to paratroopers. They could get stuck in trees and need to cut themselves out of their chutes. They needed a knife they could use with limited mobility. The traditional gravity knife had a button that released the knife that fell into place and locked by force of gravity.
These became popular later and evolved, most notably into the spring-loaded switch blade. To combat this and crime in the 70s and 80s, NYC clamped down on so-called gravity knives, which the law defined as anything that could be opened with one hand.
This law was clearly abused. NYPD officers would forcefully try and open a knife with one hand, claim it was a gravity knife and the owner would be charged. With a prior arrest this may be upsold to a felony.
This was such a problem for many professions that needed a knife for their job, most notably stagehands on Broadway and custodians. One custodian walking home at night ended up with a 5 year prison sentence with an upsold felony charge.
And of course minorities were overly targeted with this law.
Through the 2010s reform was repeatedly attempted. Twice this was vetoed by Cuomo at the behest of the Manhattan DA. Cuomo at this time I'm convinced still thought he could be president some day (to be fair, he probably could still be if he switched parties based on recent evidence) so courted the "law and order" crowd and political support from the police unions (who opposed reform) and the DA. Vague reasons were given for the veto.
Eventually this did pass but there still seems to be problems with that.
So let's outline the problems here:
1. A so-called Democratic governor choosing personal ambition over targeted minorities;
2. Arrest targets within the NYPD that drive police to meet those targets;
3. Police unions wanting more ways to randomly charge people for doing their job just in case they wanted to; and
4. Targeting of minorities, likely because they were poor (and couldn't thus afford legal representation and were also more likely to have a criminal record so the charges would stick).
For me I was glad to see Cuomo go but frankly I couldn't stand the guy long before the sexual harassment allegations came to light. It seems like every issue I looked into Cuomo landed on the wrong side of it and personal political gain seemed to be the reason. For example, NYC property tax reform and congestion charging for private vehicles in Manhattan.