They're soldiers not generals.
They have no idea how to fight a war or even recognize the new shape of the war they are in.
In the real world, Roger Cross has been working constantly for the last 20 years, even if because he's the size of a line backer the lad might be typecast as a thug with a gun, you have to assume that if he's given a part with range that he can full up all that potential because it's rude not to.
Roger's Character is a thug, which means that he probably has to subtract from who he is as a real person to create he illusion that he is a drug controlled genetically augmented dog soldier.
A couple more episodes and you'll see WHY liber8 should have been trying to mass wealth and take over the world rather than pull everything down like rancid terrorists since because they have enough foreknowledge these time travellers should have the rest of the world at a distinct tactical disadvantage.