While i agree that something should probably be done about PVP in a larger sense, I can tell you why this is going on: Honorable kills and Achievement points.
Farming big battlegrounds/bgs gives farmers lots and lots of honorables per hour. It's not about having a challenging or "fair" pvp experience, it's about getting as many honorable kills as possible. They don't care about your fun, is the honest truth. Wintergrasp also has a ton of PVP achievements and since it cant pop multiple times every hour an efficient farmer instantly switches alliance and joins the graveyard farm where the winrate in the peak hours is much higher. Again, they don't really care about you having fun or having an enjoyable experience.
The truth is, WG as a concept is just not that fun or well thought out. It gatekeeps a raid behind PVP (which I as someone who only PVPs dislike), it heavily favors multiboxers and burst damage because of the goal of the defenders being to kill demos (which is a bigger problem, arguably, on Warmane than it was back in the days in WOTLK) and forces you to do the most unfun content to be competitive in both PVE and PVP (Want to PVP? Go do wintergrasp quests because you NEED your enchantments. Want to PVE? You need to win the PVP battle of wintergrasp to be as efficient as possible every week on every char.)
IMO it's easy to blame Warmane for this when a big part of the problem really is just Wintergrasp.

