It's not about firing someone or choosing not to work with them. It's about doing it in a humane and ethical way. And unless the therapist has been threatened by the client that should go beyond just providing referrals. It's wrong and it's damaging. Therapists work with people all the time they don't really want to work with. It's the nature of the job.

If therapists really care about people then they need to suck it up and deal with their prejudices. (I'm not sure any of them really care at all though.)