On the face of it, sending un-trained US miltary personnel into the hot zone makes zero sense. So why might they have been sent?
The 101st and National Guard aren't being sent to mitigate the situation in Liberia et al. in any meaningful way. They're been sent for training.
Worst case scenario, if the virus causes serious disruption in the US, troops with Liberian experience will be used to train up stateside forces to back up health workers and quell unrest. As a bonus some of the surviving infected troops will have immunity to the virus.
OTOH, Maybe I'm giving Obola credit for a level of cynicism that isn't there. Maybe the administration really is the most incompetent in US history.
Or maybe, just maybe, the US military (or any functional military for that matter) has the only organization structure, money and manpower to deal with these sorts of major threats.
Don't you watch any televison?