Please, allow me:
1. I don't really understand this part. I think we want to enforce democracy on countries that have no history of it. I.e. the Islamists wouldn't be voted in.
2. It's more indescriminate, with children being more susceptible to the effects (particularly with chlorine) since it's very dense and is at its greatest concentration when close to the ground. Even the most evil dictator surely cannot wish to punish kids.
3. That's Merkel/Macron's problem, really. We have an sea border so need not worry. Just make sure we're checking lorries at Callais.