There are plenty of weaknesses, you just have to find them yourself. Also, antiproton streamers are essentially targeted AoE weapons. They are best used to blanket a fleet in fire, and are worthless against small and fast-moving targets.

LCF antiproton streamers are large pyramidal protrusions from the hull, the antiproton containment cells are always just below the weapon in an armored compartment. The shields of LCF ships are extremely effective against projectiles, but lasers pass right through if aimed at the hull and not the antiproton weapons (which are protected with ultra-reflective materials). That's what I'll tell you, there are weaknesses in those facts, and many more. You just have to find them.