Correct. This applies to any kind of discussion. Minds are not changed by persuasion but by changed circumstances. Search the archives for the subject Dust-up. A long debate between (primarily) Miles and Julio.
This is also the reason that in political agitation one speaks/writes only to those who already agree on some significant point. Those attracted by that means then become involved in collective practice, and their thoughts (and agreements) develop further out of that practice.
(Note: I don't give a damn how one gets people to vote. I'm talking about mass movements of the left.)
Carrol