You have to pick:

I'm assuming we can't stop them for some reason, like they've got some sort of powerful defensive magic protecting their territories? Normally I'd expect the world's militaries to make short work of dragons if they caused trouble.

Or perhaps they are just secretive. They abduct people to their secret lairs as pets.

That said, I don't think that's the intent, because I think the option is meant to make you concerned that you or a loved one could become said pet.

So yeah. I guess we can't stop them. At least not easily and currently.