But nothing about Scottish independence, even in 2014, was based upon race, religion or ethnicity. Hence why even a vague association to such remarks is sinking like a lead balloon.
I think that's a bit disingenuous when the main campaigning party is an expressly nationalistic one. We might not wish to establish being Scottish as a race, but it is often held as a distinct (perhaps near-ethnic) identity, with some historical background to support that view.
Certainly economic and social arguments were made to support independence, however legitimate or otherwise those might be. But an undercurrent of a lot of the social arguments in particular is that the Scottish are an inherently more liberal group whose progressive intentions are smothered by the conservative South as run by London.
Even if from that perspective Kahn's animosity is understandable I agree that such a direct comparison is ill-considered. But I think you very quickly run into a quagmire here: if an argument for independence isn't going to be made entirely on economic grounds (and it isn't) then at some point you are going to have to make recourse to some vaguely ethnic group identity to support an argument as for why they deserve self-rule.