http://www.economist.com/news/leaders/21707209-labours-implosion-leaves-britain-without-functioning-opposition-more-dangerous?cid1=cust/ednew/n/bl/n/20160915n/owned/n/n/nwl/n/n/n/n
Why do most commentators conflate "Scots" with "Scottish Nationalists"?
c.50% of Scots who voted in the 2015 general election voted for "Westminster" parties.
Or, put another way, only 35.5% of the Scottish electorate voted for the Scottish Nationalist Party in the 2015 general election.
So, when these commentators refer to "Scots" as a whole, what they really mean is "just over a third of Scots".
(Yes, I know that stats can be spun to fit a given narrative, but that works both ways...)