Simple answer is women can potentially get married and raise a family, transexuals know none of the men they have sex with would ever marry or have kids with them. Transexuals actually like being called sluts, because they're not banking on a beta male provider to swoop by after they've passed their expiration date. Transexuals don't care about raising a family or having a male provider, they are just happy to continue riding the cock carousel until they hit the wall, transexuals like Blaire usually hit their wall by the age 35, at that point they try to re-transition to looking like men again. Women want the family and the dog and kids and fancy wedding, but they also want to ride the cock carousel with alpha males in their prime years, and they know no man worth a damn would ever marry and provide for a 30 + year old slut and have kids with her. Only desperate beta males marry old sluts. A 20 year old slut is not as bad as a 30 year old slut, at least the 20 year old has more of her prime years left, and if the 20 year old is willing to commit to you after riding the cock carousel, be very careful not to marry her until you date her for at least 5-7 years to make sure she won't cheat on you or give you any bullshit.
Keep the spirit