I'm one of the people who leave a WZ not going my way. I admit it.
Republic on our server don't realize how much healing wins games. On the flipside, every game has at least 2 healing sorcs, if not additional healers of other classes.
If we can't even take 2 points in the Civil War when I go solo mid vs. 3 sith (meaning, there are 7 of my team members on other points vs. their 5) whats the point of staying?
I can leave, queue up, ~10 seconds later get a pop and roll the dice again, and get more honor, credits, etc. than sitting through a 10 minute fail game.
I find no problem with it.