The John Snow pub shut down for the evening Friday when its landlord learned of the planned demonstration, the Daily Mirror said.
Paul Shetler called the response to his plan "absolutely amazing."
"My friend and I were discussing what would be the most appropriate response," he said. "Rather than us just accepting that we should be hiding away from a place like this, we thought we should go there instead and have a massive kiss-in. It seemed the obvious thing to do."
The two men, Jonathan Williams and James Bull, said they were told they were being obscene when they were kicked out Wednesday.
"I felt so belittled and, to be made to feel so dirty and cheap over something like that, well, it's just wrong," Bull said.
John Garcia, a regular at the John Snow, told the Mirror he did not think Bull and Williams were sent packing because they are gay.
"They were canoodling and embracing. It looked very passionate," he said. "It did not offend me but I can see how some people would have been offended."