The reason for the anger was the poster used to advertise the event: an 'alternative' interpretation of Leonardo Da Vinci's painting, The Last Supper.
Instead of being surrounded by his apostles as in the original, the poster shows a tattooed Jesus sharing the dining table with a group of bare-chested, muscly men - some of them kissing each other.
What's more, two men in the forefront of the picture are removing their togas, one revealing bare buttocks. And behind the table, one man appears to be performing oral sex on another.
The deputy coordinator of Forza Italia's Salerno branch immediately called for the event - which is held weekly on Thursday nights at Salerno's Caffe Verdi - to be cancelled, out of respect for the local Christian community.
This week's event falls on what is known as Holy Thursday in the Catholic calendar, the day on which followers of the faith remember Jesus's Last Supper.
"The organizers are neither blasphemous, nor 'alternative' but simply misplaced and disrespectful," said Forza Italia's Fabio Mammone.
And the Popolo della Famiglia group, a Catholic political movement formed in 2016, backed the call to cancel the event, accusing the advert of "slaughtering respect and good taste".
Critics flooded the cafe's Facebook page with one-star reviews.
"I feel offended as a Catholic, because my Jesus will be defamed with a squalid show," wrote one user, Daniela Grechi, while another commented: "You will have to apologize for the rest of your life for the lack of respect towards those who believe in Jesus. Shame!"
However, supporters left positive reviews on the page, with Francesco Napoli saying: "Five stars for courage, independence, and equality."
Caffe Verdi and DiverCity, the group which organized the event, responded to the criticism on Wednesday, confirming that the event would go ahead as planned.
One of DiverCity's event planners who had worked on the event, Emanuele Avagliano, said: "We reiterate with strength and conviction our freedom to live and enjoy ourselves as we see fit", and restated that the intention of the poster was not to be "blasphemous, offensive or disrespectful" but rather "alternative".
He urged supporters to participate in Thursday's LGBT evening "with even more force and conviction, to lay claim to a space of freedom which is indispensable for the gay and transgender men and women in our city".
Meanwhile, the cafe said it could not "remain silent in the face of multiple attacks on our business from the media" and expressed "unconditional support" for the DiverCity group, which it said had hosted its weekly events on the cafe premises for two years with no problems.
"Like any business, we respect secularism and freedom of expression for each and for all" said the venue's owners, adding that they had not ruled out the possibility of taking legal action against those who had "defamed the honour and respect of our business".
Italy's first TV advert featuring gay people was produced in 2014 by frozen food company Findus, following an uproar after the head of pasta company Barilla said gay families would never be featured in its advertising.
However, the country has a history of adverts labelled as blasphemous by Italy's large Catholic community.
In 2015, fashion company Rosso di Sera came under fire for a nine-metre billboard depicting a bare-breasted nun, and just a few months later, an artwork named 'Piss Christ' - displaying a crucifix submerged in a beaker of urine - prompted backlash from local politicians.
The year before that, Brazil's Catholic Church threatened to sue broadcaster Rai for a World Cup advert showing the Christ the Redeemer statue wearing an Italy football shirt.