point is it wasn't always a dog whistle

It was used to describe indigenous people of Africa and America to promote eugenics (at least to the 19th century).

It was popularized by the Nazis as a specifically far right term, to describe anything that didnt meet Nazi ideals.

When its used to discuss culture (art, religion, etc) or traits of a person (sexuality, race, gender expression, etc), its a really blatant dog whistle.

Like everything, context matters, but it absolutely has been one for a very long time.