I don't have any problem with switches as people - there are all kinds of sexualities and I like that - the more the merrier.
My problem is with people who feel that others *ought* to want to date / see / screw them or that by dishonesty they can get what they want.
I wouldn't date a switch, the role doesn't turn me on, I don't think that ought to be an issue. I wouldn't date a submissive either, but I don't see submissives claiming that this is prejudice. Moreover, I am getting kind of tired of talking to Doms who turn out to be switches - it's dishonest, and it isn't going to make me want to date them. You then have a big argument because you don't want to date a switch, and they're claiming they're not a switch, they just happened to have a 2 year locked and chastised relationship with a Domme as a 'learning experience' to make them a better Dominant. *shrugs* Maybe that's your definition of a Dominant, but it's not mine.
Even switches have certain groups of people they wouldn't date, everyone has their preferences. If it's not prejudice when it's a switch saying no, it's not prejudice when it's a submissive saying no either.
Be who you wanna be, date who you wanna date, be tolerant of everyone else's choices, as you expect them to be tolerant of yours.