I understand where you are coming from but let us dig deeper into the language itself. Sinister in Latin means, "left hand". Also in French the word for left hand is guache which is "vulgar".

sinistersinister

adjective sin·​is·​ter ˈsi-nə-stər archaic sə-ˈni- Synonyms of sinister 1 : singularly evil or productive of evil 2 : accompanied by or leading to disaster 3 : presaging ill fortune or trouble 4a : of, relating to, or situated to the left or on the left side of something especially : being or relating to the side of a heraldic shield at the left of the person bearing it b: of ill omen by reason of being on the left 5 archaic : unfavorable, unlucky 6 archaic : fraudulent sinisterly adverb sinisterness noun

-- https://www.merriam-webster.com/dictionary/sinister

##gauche

adjective ˈgōsh sometimes gaucher; sometimes gauchest Synonyms of gauche 1a: lacking social experience or grace also : not tactful : crude it would be gauche to mention the subject b: crudely made or done a gauche turn of phrase 2: not planar gauche conformation of molecules gauchely adverb gaucheness noun

-- https://www.merriam-webster.com/dictionary/gauche

French Left Hand: https://www.collinsdictionary.com/dictionary/english-french/left-hand

Sinister etymology: https://www.etymonline.com/word/sinister