I'm not surprised. When a new arrival here asks what to play and where, the answers are quite simple:
Lordaeron for "challenge mode" PvE
Blackrock for instant PvP
Frostmourne for seasonal (heavily leans on PvE)
Icecrown, Alliance for PvP, Horde for PvE.
What happens when the threads are seen by hundreds, who want to know the same thing? Icecrown's Alliance gets filled with PvP'ers*, and Icecrown's Horde side gets filled with PvE'ers. So there's going to be huge difference what comes to PvP experience.
- Alliance goes for more serious PvP in general, because you were told to go Alliance, if you want to PvP, also roll a human if you're able, for added benefit.
- Horde goes for more serious PvE in general, because you were told to go Horde, if you want PvE. What PvP you end up doing, isn't going to be that interesting or competitive for you. And when it do, you start thinking of faction change.
* applies to blackrock as well.
Even without looking at PvP class guides, I can safely bet on every single guide recommends going for human, if possible.