Yes, it seems counter-intuitive --- but if the blitz works, you're on the QB in ~ 1.5 seconds. Would be almost impossible for the QB to throw a threatening pass.

In the case of GB/Zona, Rodgers avoided the initial rush, and bought himself more time. Even then, he made a world-class throw (to the heart of the end-zone, while scrambling).

Not saying I'd rush 6-7 --- but I'm also not convinced the EV is that much worse than rushing 3-4. When you rush 3-4, you're pretty much allowing every WR/TE to stand in the end-zone, and turn around for the jump-ball. Pick your poison.