Unless I misunderstood your point, that is a strange take that isn't close to being true. There is a large overlap of Scottish language enthusiasts who are advocates of both Scots as a distinct language and Gaelic, the demographic of the recent surge of popularity of Gaelic on duolingo are clear.

The overlap between political commentators who both insist that Scots is "just a dialect" and that Gaelic is a dying language that we should discourage is also very apparent.

The subtext is pro indy people are generally pro Scots and Gaelic, and unionists are against both of course.