That's the "honor system' part. The unvaccinated are supposed to wear a mask. They're not supposed to chose to not wear a mask because they don't feel like it. They must. But, there's no legal enforcement. So, they're their own cop in that regard. It's the honor system. They can lie, and then go maskless.
If a business is checking for proof of vaccines (which they legally can in NJ), they can enforce the unvaccinated to wear a mask while the vaccinated go maskless. So, a private business can take the decision out of their hands and be the enforcer. It's just that the state isn't doing that. For now.