Forty years ago, public views about homosexuality were extremely negative in many rich countries. As the chart shows, back in 1984, one in three Dutch people believed homosexuality was “never or rarely justified”. In Spain and Great Britain, that view was held by the majority. Perhaps most strikingly, three-quarters of Americans thought the same.
In Europe that’s mostly biological progress as the old timers are jumping into the box. Not sure why it’s still significantly more in the US. Lack of education and religious influence probably?