Why are people saying they will vote no to AV just to spite Nick Clegg?

My family had a conversation about it and they were disgusted, and frankly I agree. Even though Nick Clegg is an obnoxious sell-out, just like other politicians, he has been demonised to a ridiculous extent. And personally I can't stand David Cameron, but that won't motivate me to vote Yes, why in the world would it.