Videos showed mobs chasing people. One ended with a young boy being stomped on by a group of large men.

Talk of the violence has gripped Poland in the days since, with endless hours of discussion on radio and television.

Even as political leaders and church officials have tried to distance themselves from the violence, the campaign against the L.G.B.T. community has shown no signs of abating.

Przemyslaw Witkowski, a journalist, was riding a bicycle with his girlfriend in the city of Wroclaw on Thursday evening when he spotted anti-gay graffiti and told his girlfriend it was shameful.

Apparently, someone overheard Mr. Witkowski. A short time later, a man confronted him.

“You don’t like this graffiti?” Mr. Witkowski said the man asked him.

“I said I did not,” Mr. Witkowski responded.

The man attacked him.

Image Przemyslaw Witkowski was attacked after he spoke against anti-gay graffiti. Credit... Przemyslaw Witkowski

“He beat me badly, leaving me on the ground bleeding,” Mr. Witkowski said from the police station in Wroclaw on Friday, where he was undergoing a physical to catalog his injuries, which included a broken nose and fractures in his face. The photos of his bloody face have been widely shared across the country.

Mr. Witkowski has written about extremist groups and said he was worried for his country.

“We are unleashing things that in the future cannot be stopped,” he said. “It is happening.”