Battles of the late Third Age

[Nilpaurion Felagund]

Yes, I know, but...

'get rid of' politically unruly elements within his kingdom

That involves even the slightest hint of politics...those agitators will surely find a way to go to Moria, whether sanctioned or not, or if Dain stops them, they might stage a coup. I know they wouldn't win (unless they're more than I think they are(reminds me of Matchbox 20...just a stray thought...)) but they could do damage to the kingdom. Now I know Dain's aim is not to quash dissidents, but to protect the kingdom, and the best way to do it is to preserve status quo, minus the unruly ones.