It's something to the effect that the interests of every different grievance group "intersect" in that they all suffer "oppression" by the big bad ${oppressors}. The name used for the ${oppressors} changes from time to time and group to group — sometimes it's "patriarchy", since the election it's "white nationalists"; many other names have been used.
Same ${oppressors} for all, and the same solution for all: more government. That's the "intersection".