It's not about the cowardice, it's about the Symbiote who hates Spider-man being bonded to Spider-man's biggest fan.
I just got the issue today, and just read the short origin story. Spoilers below:
The government is taking every precaution to prevent the Venom symbiote from taking control. The suit is only worn 48 hours at a time, it is sonic-ed off at the end of that period, each Venom recruit has precisely 20 field missions before the suit is taken away from them permanently and passed to the next guy, and there is an implant in the soldier's head that will "nuke his brain" if the symbiote starts to overtake him. Additionally, each subject is picked for their strength of will and dosed with chemicals that retard the symbiote's ability to take control over the host while making it easier for the host to control it. Flash is selected for his heroism and his desire to receive powers like this, Flash jumps at the chance to serve his country as Super-Soldier Spider-Man. The program has already claimed the life of the first test subject, though Flash is seeming more successful at remaining in control.
They didn't just decide "hey, the symbiote is totally docile now". They take pains to explain that keeping the symbiote in their control is very hard.