A pub poster inviting Valentine's Day speed daters to "bag a slag" should not have been banned, campaigners said.
The Old Angel in Nottingham was forced to cancel its event, after the city council said the advert was inappropriate.
The Freedom Association accused Nottingham City Council of being the "arbiter of good taste".
The council defended the ban, saying an offer of free shots for female drinkers was also to blame.
The poster featured song lyrics, "Die die my darling" and the slogan, "Bag a slag, grab a hag".
Andrew Allison, from the Freedom Association, which defends freedom of expression, said: "The fact is the poster isn't inciting hatred, it isn't inciting violence, so therefore it isn't illegal and the council shouldn't get involved.
"I find myself defending a lot of things I might find offensive or distasteful. I don't particularly like the poster, I don't think it's great, but because it's not breaking the law it shouldn't be banned.
"The council isn't the arbiter of good taste."
Deputy leader of Nottingham City Council, Graham Chapman, said it was the combination of the "misogynistic" slogan and the offer of free shots for women taking part which "damaged" the city's image.
"This pub was labelling woman as slags. It was then encouraging them to get drunk by offering free shots, then inviting a lot of blokes along to get drunk along with them with some expectations," he said.
"The combination of that was not responsible. It was not something we wanted to risk."
Mr Chapman said he could not confirm whether the council would have intervened if free shots had not been offered.
"Nottingham had a reputation about 10 years ago of being somewhere where people were drinking on the streets," he added.
"We are very sensitive to make sure the image of the city is right because it does a lot of economic damage. This wouldn't have helped."
Poster designer and barmaid at the pub, Lydia Hunt said: "It was just to have a laugh and grab attention.
"I'm not saying women are either slags or hags, but I think it is an empowerment thing."