This is from the BBC Proudly Single
But India remains a largely patriarchal society where more than 90% of marriages are arranged by family and women have little say in who they marry - leave alone whether they want to marry at all.
The expression in bold in the above text "leave alone" seemed unusual to me, because I think it should have been "let alone". Leave alone means "not to disturb" someone. I checked this on some dictionaries.
Can "leave alone" or "let alone" be used interchangeably in this sense? (not in the sense of "not disturbing someone?")