No need to go off track with much of a discussion about that here, but Dylan Roof was clearly a troubled dude. He also apparently, for a considerable period of time, consistently held white supremacist beliefs and committed the shooting motivated by those beliefs.
Now I don’t know enough to come to any conclusion about this guy yet, but he voiced frustration about his divorce and discussed wanting to kill his family in a “celebration.” Then he discussed having a dream about joining ISIS, like he just had that dream and planned to join ISIS on a whim. Those reports suggest erratic behavior that does not involve much “political” or cohesive thought.