1. Bomb them back into the stone age. That would kill a whole bunch of people, who as you point out are basically held hostage by their government and don't get much choice in the matter. It'd also permanently wreck their economy and infrastructure, cost lives on both sides, and usually has follow on effects.
2. Do nothing and allow things like funding terrorism, selling arms, committing atrocities, etc. You would know these things are going on, and therefore be allowing them to happen, and these things would probably be happening to your own people and allies.
Which one would you rather take?