In the viewpoint of increasing anticipation of a stutter, "it's okay to stutter" reinforces this viewpoint. It's not about believing your stutter trigger "I will stutter now" where you think the meaning is true, it's about disconfirming expectancy, learning that the anticipation "I will stutter now" is not real in your mind. If you react to this trigger (by justifying compulsion), then you make the trigger real in your mind (attaching importance). It's about making it less important, by removing its meaning (detaching importance from the trigger). So that the next time you see a feared letter coming, that you let go (by not reacting) and just speak with uncertainty to build tolerance against the anxiety of this trigger