That knife law is pretty stupid. when I was working as a mover in NYC I carried a similar knife, as just as u said, it's useful for cutting things like tape on boxes with just one hand. If someone wants to stab someone, then they can easily get a kitchen knife and conceal it. Makes little sense to worry about the tool used in a potential crime, but much more sense to work on prevention, by engaging with marginalized communities, educating, more visible policing, etc.

Plenty of stuff is illegal somewhere - drugs, sex, rock n roll, firearms, thoughts ...

Generally I advocate freedom to do whatever you want, as long as you're not bothering or endangering anyone else.

G