I've read threads like this in the past before I pvped, and totally agreed, I hated go already. Then when I did start I think I understood the other side also.
I think it exists here mostly for two reasons;
Seems more of a fair fight. Less rushing/teaming represents an earned kdr based on skill.
And generally pvp is so uncivil that this ritual of politeness makes for a better environment.

Now I don't totally agree or disagree either way, it exists because people see some value in it, so it perpetuates. I'm guessing why here.