In designing the Bi Pride Flag, I selected the colors and overlap pattern of the bi angles symbol. I selected, which to me, is the most attractive combination of pink, purple and blue. In flag-maker parlance this is magenta - PMS 226 (pink), lavender - PMS 258 (purple) and royal - PMS 286 (blue).
You are correct
https://web.archive.org/web/20010801185547/http://biflag.com/Activism.asp
According to wikipedia those hex values are #D60270, #9B4F96, and #0038A8
I still think the colors in the meme would make a good Lemmy theme though.