Some conservatives are hailing a victory for religious liberty in Michigan, but there’s less to it than meets the eye. On Sept. 26 a federal district court ordered the state to continue allowing St. Vincent Catholic Charities to participate in its foster-care programs. Judge Robert Jonker’s ruling makes clear that the Supreme Court’s decision in Masterpiece Cakeshop v. Colorado Civil Rights Commission (2018) gives life to some lawsuits over hostile treatment of religious believers. But it also shows the limits of the majority opinion in Masterpiece Cakeshop, which doesn’t do much to secure the substantive rights of religious objectors.

As Judge Jonker notes in the first lines of his opinion, “no one in the case contests” that “same-sex couples can be great parents,” and as a contractor in Michigan’s child services program St. Vincent has placed children with gay adoptive parents. But the Catholic agency declines on religious grounds to carry out home studies certifying gay and unmarried couples, instead giving them referrals to one of the many other agencies that are glad to serve them. In 2015 the Michigan Legislature passed a law specifically aimed at protecting religious agencies’ right to opt out from home study services in this way.

Enter Dana Nessel, now the state’s attorney general, who in her successful 2018 campaign denounced that exemption as one whose “only purpose is discriminatory animus” against nontraditional families. Three years earlier she had even described its proponents as “hate-mongers.” On taking office, she declined to defend the law against challenge and instead reached a settlement with the ACLU to reverse the state’s policy.

Judge Jonker found that Ms. Nessel’s actions added up to a course of conduct that improperly “targets St. Vincent’s religious beliefs” and triggered strict scrutiny of the state’s actions. Finding those actions unlikely to survive scrutiny, he granted the charity a preliminary injunction pending full trial.

Much of what Ms. Nessel did, from zealously denouncing the exemption to acting on her opinions once in office, is the sort of thing one has to expect from any political figure with strong convictions. But even in our charged political environment, the phrase “hate-mongers” is a hot one. If Judge Jonker’s rebuke to Ms. Nessel stands up, that ill-considered phrase—rather than substantive constitutional protections for religious objectors—is likely to be the principal reason.

Compare Masterpiece Cakeshop, in which Justice Anthony Kennedy found that the Colorado Civil Rights Commission had violated free exercise in proceedings in which one of its members had described the defendant baker’s religious opinions as “despicable” and compared them to arguments made on behalf of slavery and the Holocaust. Had the commission conducted itself in a more civil fashion and come to the same ruling, it might not have been overturned. Moreover, those remarks were made as part of a process charged with bringing impartial adjudication to individual litigants’ cases. Legislators and other public servants who are not tasked with executing or applying the law impartially—not to mention private citizens—aren’t always required to show that level of detachment.

And that principle—that words of hostility can sink a policy the government might otherwise have successfully defended—cuts many ways. Justice Sonia Sotomayor quoted Masterpiece Cakeshop in dissent last year to argue that President Trump’s comments about Islam and Muslims should be interpreted to show that hostility toward a religion motivated his travel ban. Inviting judicial scrutiny of campaign-trail insults might discourage some campaign talk worth hearing (if only so as to warn ourselves) while slowing subsequent changes in policy, whatever their merits.

Where judges find no examples of insults or invective, there often isn’t another remedy available for religious objectors. In April the Third U.S. Circuit Court of Appeals rejected a request by Catholic Social Services for a preliminary injunction against Philadelphia’s no-exceptions antidiscrimination policy. Finding no remarks contemptuous of religious beliefs, the court applied the general rule from Employment Division v. Smith (1990): So long as a law is neutral on its face, of general applicability, and motivated by something other than hostility to religion, the Constitution doesn’t require a religious exemption. (Nor does it oblige, in either the Michigan or Philadelphia case, a searching look at whether kids benefit from the government’s forcing out foster-care agencies.)

Once officials learn to mind their tongues, religious objectors are likely to go back to losing most exemption requests under Smith. The only consolation is that they will endure fewer insults along the way. Or, as some religious advocates have begun to urge, religious objectors could begin building a case to revisit Smith—which would set up the biggest religious-liberty battle at the high court in many years.