Cersei/Jaime is an abusive ship, that would be an awful parallel
True. My point was that Jon and Sansa think they are siblings, and Jaime and Cersei are actually siblings. Jon/Sansa is a much healthier and better ship than Jaime/Cersei. This parallel isn’t saying that these two ships are similar, but only serves to highlight the stark difference (excuse the pun) in each ship’s morality. Moreover, from Littlefinger’s perspective (if he is unaware of R+L=J) Jon/Sansa isn’t any better than Jaime/Cersei. Which adds to the dramatic irony of the situation and makes the moment when he, and everyone else, finds out, that much sweeter.