But... the Empire was the first to call a peace meeting (Which was ignored) and try to handle the situation in a peaceful manner. Black marsh promptly ignored it until it suited them to use it to their political gain
It was only when Takar was burned and the North retaliated that the Empire became involved in anything past trying to establish talks, Elsweyr is mostly settling it's self, the Imperials haven't really done much major military action except disrupt supply routes.
The Civil War has been bad, yes, but it's really unfair to lay the blame at the Empires feet when it's been established the first aggression was from the South and the Empire hasn't really done anything militarily until my most recent post