Troll Caster Minions are punishing allies for doing good.
Enough allied caster minions will completely cut off access to the enemy turret.
They will form a troll line to block off access and you have to go elsewhere or wait for the turret to kill the melee minions before it can kill some casters making room for you to slip through, until then you're fucked..
Its, Its just really really really bad.
GOOD JOB RITO