I'd be more concerned about RH and its own incentives (look at the clusterfuck that's GNOME) than the US Army specifically.
The Interface Stability Promise [1] by systemd team is just a promise, nothing more. I wonder if Red Hat will keep it if it decides that it no longer serves their bottom line.
[1] http://www.freedesktop.org/wiki/Software/systemd/InterfaceSt...