multiple handles

I really have a problem with people who post under multiple names. I don't understand why it is necessar. It strikes me as deceitful. You build up trust with people and when you don't know who you are speaking to its hard.
What are other's opinions on this matter? I understand why people want to be anonymous and that's why some of us post under pseudonyms but having multiple personalities is weird. It makes me wonder how many people actually post on this board.