You made me think about this harder than I thought I would. I’ll take a stab at it and call it something like an embittered, self conscious or self aware attempt at optimism. Or positivity for those to whom it doesn’t come naturally, still with the self consciousness or self awareness. Though not necessarily self consciousness of the curse words themselves but of the dual emotions.

But this is assuming that this cartoon is intended as the inner monologue of the rabbit, which seems to be the case. If there was an intended audience within the cartoon then it would just seem like some kind of pretension.

Edit: added “or self awareness” twice because I’m not sure what I’m getting at precisely