OK, I admit its silly: unicorn clearly are not butch enough either. But there is a fun aspect to both the flag and mythology which we give up too easily in our oh so serious need for respectability and acceptance. For some, the flag doesn't fit with our Real Jock culture of "uber masculinity"
Borrowing heavily from the Hippie culture, the colours supposedly reprise key aspects of "the life"
hot pink: sexuality
The pink triangle - used during the Nazi internment of Gays to stigmatize them during the holocaust (go read about it) - was turned on its head from a symbol of shame to pride.
Many men could feel more comfortable with more aggressive, male symbology (eg tribal patterns used in tattoos) and colours (blue instead of pink), but that's not true for lesbians, trannies and many others.
But what inner demons and insecurities really drive us to conform, to consider a colour "effeminate"?