I am aware of Lavender Linguistics, which is a form of Polari and was used by gay men a lexicon 'used in the 1950s and early 1960s by gay men as a secret language which concealed their homosexuality in the face of the repressive society of the time.'
- Wiktionary doesn't offer this definition.
- Etymonline mentions 'camp followers' (which I presume means homosexuality) but not anything further than that.
- Lexico gives a definition of 'Used in reference to effeminacy or homosexuality.'.
I thought Why Lavender? - The University of Nottingham would help, but instead it speaks about the reason a conference uses the term lavender, reiterating its use in the 20th century to denote homosexual people:
‘Lavender’ was seen to be a neutral term which would not exclude particular research foci...
In short, I know that it is used in this way, but why did lavender become associated with homosexuality?
I assume it is because purple is regarded as feminine, but can't find anything to back it up.