Few things that I know about the band for when I worked in the music industry:

Lead singer liked his names spelled “Gene SSimmons” to honor the nazis

The tongue gimmick was a reference to licking up tears of the Jews that the nazis claimed to enjoy doing as they got on the train or into aushcwitz

The song “Heavens on Fire” was renamed after Gene called it “Heebs on Fire”, heeb being a racial slur
…
They stopped playing them on the radio after he held the concert in Dallas where he told the crowd to hell Hitler but they should have been stopped way before that.