[jet]

Originally Posted by Vanessa

hazel is hated because of the whole daley thing. If it wasn't for that she'd be more popular.

Yes, but the HM's may not know the full extent of her flirting with Daley. For example, Dan wasn't around a lot of the time that she was doing it, and the others individually weren't always there either. When the other HM's did see it, they wouldn't know what was actually being said between the 2 of them.
We know, because the highlights concentrated on it, and Gina and Dexter know as they watched from the safe house.
I think Dan is just trying to work out why his friend is hated so much, and isn't a big leap for him to think that D&G saw things he and the other HM's didn't and he could well think that they are targeting Hazel for that (which is partly true!)