Why isn't the 2.5-mile walk an alternative aerobic event in the ACFT?

Because I think this is a way of getting rid of the walkers. I see that the bike is still an alternate event, though.

While a fast paced walk for a longer distance may be an aerobic work out and mimic what may happen in real scenario that tests an individuals cardiovascular fitness, it may not be equivalent to the standard that the army is looking for.

Uh....because it's called the Army Combat Fitness Test (ACFT); combat being the key word here. When rockets and mortars are raining down, are you walking to the bunkers?

Yeah, they need to include the 2.5 mile walk in this new PT test, if they plan on keeping it, because they will lose a lot of Soldiers. We all get injured either temporarily or permanently and with the walk a soldier can still perform aerobically. I do not know of anyone who will be running 2 miles continuously in combat. More than likely it will be a combo of running/jogging and fast walking. Walking hard and fast takes a hard toll on the lower legs and it is more painful if you are not used to it.
Unless they have an alternate jogging time for those who cannot run and lengthen the time they get to finish, then eventually the Army will be screwed out of some good soldiers knowledge and skills. They will have a lot of soldiers failing the PT test or pushing through and getting even worse injuries.

That's a very good question. I find that speed walking is much more difficult for me than the pt test run. I'm glad I didn't have to speed walk and get scored on it.
I'm not even kidding.