Visa and MasterCard confirmed that they have cut off payment services for Backpage.com, an online platform for people to advertise goods and services. This was in response to public pressure from Cook County Sheriff Tom Dart, who wrote to executives at both of the payment processors urging them to cut off transactions to Backpage’s adult services. The two companies responded by quickly shutting down payments for the entire site.

Backpage hasn’t violated the law, and so Sheriff Dart can’t use the law to take down the website. Instead he’s using a tactic we’ve seen before, getting major financial services companies to put a chokehold on controversial online content producers like WikiLeaks and independent book publisher Smashwords.

We don’t need Visa and MasterCard to play nanny for online speech. Payment processors and banks shouldn’t be in the position of deciding what type of online content is criminal or enforcing morality for the rest of society. For one thing, their businesses haven’t been designed to analyze the legal and societal issues at play in various forms of online expression. Second, these businesses will almost always err on the side of shutting down controversial speech—thereby eliminating a nuisance or public affairs problem—rather than taking a principled stance in support of unpopular speech.

That’s why courts, not companies, should determine what type of speech is legal on the Internet.

Backpage.com can be used to sell an old refrigerator, find a new apartment, post about new community workshops, find a job, and offer many other services and goods. It also hosts an “adult” section of the site, where some people advertise escort services or try to connect with people who have similar sexual interests. This “adult” section requires visitors to confirm they are at least 18 years of age and allows users to get resources for reporting cases of suspected sexual exploitation with one click.

Dart asserts that he’s concerned about people abusing Backpage.com for nefarious purposes such as human trafficking, even though the site isn’t designed with that in mind. And he’s not the only one: politicians and law enforcement agents have been pressuring Backpage.com for years to shut down the adult section of the site

Let’s stop for a moment and acknowledge one area where we agree wholeheartedly with Dart: human trafficking is atrocious. We strongly condemn the violation of human rights that occurs whenever a human being is sexually exploited or forced into physical labor against his or her will. Human trafficking is a massive human rights issue that deserves focused, dedicated attention from lawmakers, law enforcement, and the public. It’s also a heinous crime that merits severe punishment for those who perpetrate it.

Backpage, however, is not engaged in human trafficking. It shouldn’t be treated as if it were.

The law is on Backpage’s side. To date, attempts to pass laws that would hold a website accountable for the content posted by users have been defeated, such as a Washington state law EFF successfully fought in 2012. Backpage is also protected by Section 230 of the Communications Decency Act (CDA 230), which ensures that websites that host content—like WordPress, Facebook, and others—aren’t liable for the content of the messages that their users post. And that’s a good thing. This law has been a cornerstone for free speech online, ensuring that Web hosts don’t have to police their users and can focus on providing a great experience–even if their users’ views are controversial or unpopular. As we’ve argued before, CDA 230 protects Backpage from liability for user-generated advertisements.

One could imagine a world where we had many payment providers, each operating independently, to ensure that even if one major payment service caved to governmental pressure there would be many others to offer services to less popular sites. But that’s not the case. Instead, the overwhelming majority of online payment services are connected to MasterCard and Visa. So when they both shut down a website’s services, the business must either acquiesce to their demands or risk going out of business.

We appreciate that Visa and MasterCard may be facing serious pressure from law enforcement, both in this case and in others. But we’d urge the two financial giants to strive for neutrality in offering payment services and resist government requests. And that starts by reinstating Backpage’s services.

As for Sherriff Dart, we wish he’d turn to the real problems of human trafficking and exploitation. Rather than attack neutral websites and payment providers, law enforcement should focus its investigations and enforcement efforts on actual criminal suspects.