Since we are still learning about the dangers of football, for example, it is neither prudent nor moral to expose more athletes to an unknown degree of risk. This is especially true when professional fighters do not have the protection of an organization like the N.F.L. Players Association. Mixed martial arts fighters are “gig economy” workers with little recourse should they find themselves unable to work through injury. Assemblywoman Deborah J. Glick, who voted against the bill, said she found it very painful to think of “youngsters who may think this is a way to gain notoriety.”

Regulation cannot reduce a harm if it encourages more of the activity that causes that harm. The mixed martial arts industry wants to grow; that is why it has lobbied so hard for legalization in the wealthiest city in the nation. In the case of hydraulic oil and gas fracturing, or fracking, the state chose to study the issue before disallowing what the governor and others saw as a potentially dangerous activity. But here, lawmakers want to allow people to engage in a definitely dangerous activity in order to study it.

The economic rationale for legalizing mixed martial arts is also misleading. As New Yorkers participating in mixed martial arts end up suffering traumatic brain injury and permanent disability, the state will most likely end up footing part of the bill to support them. The argument is a miserable one: Has the Empire State fallen so low that it cannot find work for its young people without purposely putting them in harm’s way?

To the lawmakers who said they hated to see people leave New York to see a mixed martial arts match elsewhere, the answer is, “Let them go.” Just because there are people willing to pay prostitutes or purchase street heroin does not mean the state should be obliged to legalize these harmful trades.

There is one final reason Mr. Cuomo should veto the bill: Legalizing mixed martial arts would be a stain on the state’s proud progressive heritage. New York was the first state in the union to prohibit drunken driving and to enact seatbelt laws. For more than a century, it has been a national leader in public health and workplace protections.

Is the Empire State no longer an enlightened standard setter but so desperate a laggard that it will allow citizens to suffer repeated concussions because it’s eager for the money and the jobs? The state cannot stop violence as entertainment elsewhere, but the governor can remind the rest of the country that it’s not a New York value.