WARSAW — By the standards of Western advertising, Coca-Cola’s billboard campaign in Hungary was pretty tame.

Three couples are shown enjoying a soda, smiling and seemingly in love. One picture shows a man, a woman and a Coke; another two women and a Coke; and a third shows two men and a Coke.

“Love is Love,” is the campaign slogan. But in the current climate in Eastern and Central Europe, where “L.G.B.T. ideology” has taken the place of migrants as public enemy number one for many nationalist leaders, love is not love.

It is a threat.

Soon after the Coke ads appeared, a pro-government internet news site ran a banner headline: “The Homosexual Lobby Has Now Besieged Budapest — They Won’t Give You A Chance to Avoid It.”