Solidarity has always been a Leftist buzzword. Intersectionality is the modern incarnation is allying Leftist factions under a larger socialist effort, exactly the same way that Solidarity was used for.

You're making the same kind of "left-libertarian" argument that "Social Justice activists aren't advocating for Social Justice". Yes, they are, you're misusing the term because you're applying the "useful idiot" definition that all the Leftists laugh at you for using.