NJ, certainly the Scottish electorate "chose" not to go for independence, but that is a whole different ball-game, as they say, from the SNP fielding candidates only in Scotland, since that had nothing to do with “choosing” at all!
Or are you seriously suggesting that you yourself would have found nothing whatever odd on May 7th, in your own parliamentary constituency, about seeing the names of candidates from Plaid Cymru, the Democratic Unionist Party and the Scottish Socialist Party on your local ballot form?