Because they have mommy and/or daddy issues and lack the validation and attention they so desperately seek from their parents after being neglected in some way during their childhood (whether they’re conscious of it or not) and for them any sort of affection or validation equates to love in their minds. However they are unaware of any of this and will be until they realize that validation and attention does not, in fact, equate to love but until then they will continue to be femboys and jump at any chance they get to feel loved by anyone willing to provide it.