It's more that, as an end-user, I do not care whether I click accept or reject all; my goal is to get that UX speed-bump out of my face as quickly as possible.
Maybe it'd be better to randomize which button is selected so if the plugin becomes popular site admins can't reliably guess where to put the button.
Why do you think the left-most button is always accept all?
Why do you think the accept all button will be in the same position on all reloads of the same site?