I find it odd that the military was so ill prepared for stopping the group of refugees that they immediately resorted to slaughtering them. Not that what they are doing is necessarily wrong for the time, but it should still have been the worst case scenario response.
It would have made more sense to at lease keep them alive if possible, since you can't tax the dead, and the dead can't produce. 1000 is also not a small amount to lose. It easily is a village or 2's worth of citizens. It is odd that they barricaded so close to the border too, though maybe that was unavoidable.
It does seem at least like they are choosing to make a statment though. Almus would obviously have to return any refugee that crossed since it would be impossible to hide it. So them choosing to slaughter all who even attempt to cross seems more like a jab at Almus rather than preventing escaping refugees.