Scotland’s First Minister was elected by the Scottish Parliament in 2014 and then by the people in the 2016 Scottish elections. With Boris Johnson being elected by only 0.13% of the UK population, he has no right to lecture anyone on democratic legitimacy.
The Tories and Brexit have been rejected by the people of Scotland on numerous occasions. Boris Johnson does not care about Scotland. He only cares about himself. His patronising response on his first day says all you need to know about his character.