At a protest in San Sebastián, Spain, earlier this week, demonstrators carried a banner that displayed a swastika followed by an equal sign and the Star of David, signifying that the swastika equals the Star of David.

The Combat Antisemitism Movement called out the moral inversion of the protesters on social media.

“The swastika represents the regime that murdered six million Jews,” the group wrote. “The Star of David represents the Jewish people. Sickening.”

Viewed this way, the protesters can be seen as once again calling for the genocide of the Jewish people.

The Star of David is an ancient Jewish symbol whose use originated in 14th-century Prague and spread to other Jewish communities over the course of the following centuries before its universal adoption as the symbol of Judaism in the 19th century. Critics point out that equating the swastika with the Star of David is no different in its moral repugnance than equating it with the cross, the symbol of Christianity; or the red crescent, the symbol of Islam.

Two similar cases in the past year have also ignited backlash.

During graduation week at New York University last month, a banner displaying the Star of David flanked on each side by a swastika was spotted by students celebrating the end of their studies. The offending flag was swiftly removed, and N.Y.U. released a statement denouncing the act.

“We are shocked and deeply troubled that this hateful symbol expressing antisemitism was raised on a flagpole overlooking Washington Square Park,” N.Y.U. spokesperson Wiley Norvell said in a statement. “Campus safety responded immediately to remove it, and we are working closely with the N.Y.P.D. to identify whoever is responsible.”

On Holocaust Remembrance Day last April, a Polish MP held up an Israeli flag whose Star of David had been replaced by a swastika in a floor speech in which he denounced Israel for committing “genocide” and compared it to the Third Reich.

“Israel is the new Third Reich, and its flag should look exactly like this,” Konrad Berkowicz said as he held up the flag.

The antisemite was immediately repudiated by the house speaker in real time, and Israel’s Foreign Ministry issued a blistering condemnation.