The Rhunkit are not part of the Cult of Thungni or the Guild of Runesmiths, but the Cult of Thungni argues that all practitioners of Runesmithing are under their jurisdiction. Karak Vlag seems to disagree.
Ah...I see the conundrum.
They swore no oaths, have taken no initiations, and those who might be grudged with the breach are long since stone, having done so under the actions of the Four.
As far as laws are concerned, they're green. Heck, they hadn't learned anything beyond Apprentice level craft, everything they know they discovered for themselves!
The Cult is left with Tradition, but they do not share a tradition. The Cult of Thungi cannot shame or socially pressure those trapped alone within Slaanesh's grasp for generations.
They cannot impose economic sanctions on an autarky.
They'd have to be insane to wage war on a dwarfhold which had been under siege by daemons for centuries, nevermind the social consequences of striking at a returned Lost Old Hold .
And yet if they tolerated it, it would be a Precedent, they would have to establish an exception.
Man, this must give them a giant ulcer...cursed with fortune indeed.