IF you have time to do both hardcore that is great. What I'm saying is most people who work 5 day weeks dedicate most of their time to either one or the other. Every guild I have been has followed this example. I'm NOT saying the guild is DEFINED as a pvp or pve guild, but the players inside will usually devote MOST of their game time to either pvp or pve.
I am not saying, as you suggest, that PVP'rs wouldn't absolutely smash PVE content. I agree with you on that. The point is they either can't be bothered, don't have the time, or just would rather spend their game time doing what they love - PVP.