I will say yes, there IS a difference between a competitive and dutiful player. In the absence of a competitive one, I'll take a dutiful one as, like you said, they will at least do their best. That is a far cry from that other person's idea of "letting the other team win to get it over with quickly".

That said, let's not make competitiveness sound like a bad thing. There are extremes, yes, but barring that, being competitive doesn't mean winning above all else, even your own fun. After all, isn't it more fun to win? I won't spark up the old "I play for fun" debate as that has its own flaws, but being competitive doesn't mean you're not having fun. Competition itself can be part of the fun. At higher levels, I know most competitive players enjoy a good fight more than an easy or guaranteed win.

Where my post diverged was both addressing you, and the original statement I criticized, and I perhaps wasn't clear between the two. What that other player said about letting another team win to get it over with is not okay at all, and I stand by my words on that. That kind of defeatist mentality was not present in PvP before they added XP as a reward, and it has no place there, competitive or not, XP or not. But it can't be overlooked that it became an issue once XP was offered, and that's a reason why some players who actually want to enjoy PvP want to see XP removed.