In the spring of 2021, Chet Hanks, the singer, actor and son of Tom, posted a series of statements and a music video with a refrain that caused confusion, not to mention a fair bit of cringing. He declared it was going to be a “white boy summer.”

Whatever exactly he meant at the time, the phrase has since mutated into a slogan for white supremacists and other hate, according to a report published on Tuesday by the Global Project Against Hate and Extremism, an organization that tracks the spread of racism.

Thousands of posts using the slogan “white boy summer” have appeared on the Telegram app this year. It’s been used by far-right groups to recruit new followers, organize protests and encourage violence, especially against immigrants and L.G.B.T.Q. people, the report said.

For many of those who use it now, the phrase represents an unapologetic embrace of white heterosexual masculinity, often at the expense of women and people of color.

Increasingly, the meme has moved from the fringes of the internet into the political mainstream in the United States and elsewhere around the world, one of the group’s founders, Wendy Via, said.

Jack Posobiec, a podcaster whom the Southern Poverty Law Center has linked to white supremacists, waved a banner with the words “white boy summer” on it at a gathering for Turning Point USA, a conservative group, in Detroit last month. Former President Donald J. Trump was the conference’s keynote speaker, along with several members of Congress.