Reid as written in slash

[renee7931.livejournal.com]

I've noticed in Criminal Minds slash, Reid is always the submissive partner. On the show he's portrayed as somewhat shy at times, but not necessarily a submissive type of person. Why do you think he's written this way? Is it realistic for him to always be written as the bottom? Why isn't he written more as his partner's (Hotch, Morgan) equal?