Your hubs were probably marked duplicate because the information was posted elsewhere on the internet, which is frowned upon. HubPages is a website to write information on, it's not necessarily specifically to link your blog to, as this can be conceived as being spammy if that's your sole purpose.
Marking the hubs as duplicate, isn't un-hub-like, as the TOS pretty much say don't post copied content on a hub, whether it's yours or not, if it's elsewhere on the internet, they really don't want it here. It doesn't look good for SEO to have the same content in multiple places. They're just giving you a warning; they'd unpublish it if they felt it needed to be unpublished.