Well, they both do use dream sand in the movie, so I wouldn't be shocked if a large chunk of people thought they were related. They are also both extremely dramatic with their facial expressions and body language.
I love Pitch too...and if you think about it, Pitch is actually the most important Guardian of them all. Fear keeps us safe, I would rather have my kid's afraid to cross a busy road without me than have them hope or believe that they can do it alone. So I belive in you Bogeyman, keep scaring us all, we all need a healthy dose of fear once in awhile to keep us on our toes.