Dozens of protesters descended on a hate-mongering Brooklyn coffee shop Wednesday morning after it publicly vowed to refuse service to a pro-Israel politician and its owner’s social media posts comparing Israel to Nazi Germany came to light.

They chanted “end Jew hatred” and “this shall not stand” as they were confronted by a smaller group of counter-protesters — many of them rabbis from Jews Untied Against Zionism — who waved Palestinian flags and loudly denounced Israel through a bullhorn.

The sides angrily clashed on the sidewalk in front of Poetica Coffee in Park Slope, at times shouting in each other’s faces, until the NYPD stepped in and cordoned them off in separate areas.

“We will not allow businesses or individuals to discriminate against anyone, including Jewish people, simply for supporting Israel, which is the only Jewish community in the whole world,” said Daniel Rosen, president of the IMPACT organization, who just arrived in New York on a flight from Israel.

The shop excoriated NY Rep. Dan Goldman on social media for buying a cup of coffee at their location over the weekend, posting his photo and asking if their coffee tasted like “genocide juice” in an unhinged rant.

“See, here at Poetica, we don’t serve racists, fascists, homophobes, genocide enablers, or anyone in between,” the shop boasted online, demanding he never again set foot inside the shop again.

The incident prompted the Justice Department’s Civil Rights Division to open an investigation, and warn that an enforcement action against the shop could be coming.