I think you have some formatting errors with the start of your comment.

Jack's point is that among the plausible reasons to want to avoid the subject is a desire to not have the fight associated with the subject. That her strategy involves picking a different fight doesn't take away from the point that she has plausible fight related reasons for not talking.

I see how Alice's strategy is different; I don't see how the subject of the fight is different. In example 1, Bob says "let's talk now" and Alice responds with a subtextual "no." In example 2, Bob says "let's talk now" and Alice responds with a textual "no, how about later?" Is that enough for you to call it a different fight?