It means they really don't care, which shows in their product. My chats often get lost or delayed. I can't control my "contact" list, and there is no reason why I shouldn't be able to except they don't want to allow it. I see my friends who have died 3 years ago still on it, and I can't remove them unless I block them. If my contact is "Off the Record" they don't even show up in the list, which is infuriating.
I would love to know the reason why they let Gmail and Gchat go. My killer app for the Mac is iMessage, mainly because it integrates my text messages and Gchat into a single client. It's so convenient throughout the day for me.