Some military procurement officer can check me out on this--but the Hummer was designed to replace the venerable Jeep as an all-purpose unarmored utility vehicle, not as an armored fighting platform.
Utility--you know--run the troops and Generals around behind the lines, go for supplies. Refitting armor onto it over-strains the design capacity of its parts so they break down more often.
The armored vehicle for fighting infantry battles is the Bradley and the new Stryker.
Yep, you got it.
Yes, but what is "behind the lines" in Iraq? I am sure that in a more conventional theatre of combat, the unarmored hummer does the job, but in a theatre such as Iraq, you need something lighter and more mobile than the Bradley (wheeled). Now, I wonder why the wonder machine (read Stryker) isn't the vehicle of choice. That is the real question.