Massimo Arcangeli was clarifying details of the couple's stay with the owner of the family-run guesthouse in Santa Maria, a hamlet near the beach resort of Tropea, via the messaging service when he was told that gays were not accepted.
He posted the discussion on his Facebook page. The owner asked questions about where the couple was from and gave details of the guesthouse adjoining the family villa before thanking Arcangeli for booking to stay, adding that it was the first year they were renting the home to holidaymakers.
But then the owner ended the message with what he described as an “important” notice:
“I'm sorry if I seem like a caveman. We don't accept gays or animals.”
Arcangeli said: “It immediately made me think of the famous message Nazis would post on their shop windows: ‘No dogs or Jews'. Seventy years have passed since then and this story cannot be ignored.”
The Italian gay rights association, Arcigay, has called for the hotel to be removed from Booking.com and other hotel reservation sites.
The association's Naples unit said it was “disgusted” by the hotel owner's conduct.
“We also look forward to decisive action being taken by the municipality, the Calabria region and authorities responsible for supervising and combating discrimination.”
Italy may have reached a "historic milestone" in granting civil unions in 2016, but the county is a long way from being LGBT-friendly, according to a report published by Rainbow Europe in May.
In the report, Italy scored just 27 percent in its protections for and rights granted to lesbian, gay, bisexual and transgender people (LGBT), making it one of the worst countries in Western Europe in terms of gay rights.
However, its ranking of 32nd out of 49 countries was an increase of three places from the 2016 ranking, when it scored just 20 percent.
LGBT people in Italy are also at risk of homophobic violence, the report said, citing a far-right attack on a Rome Gay Centre, and five murders of trans people in Italy in 2016.