In Game of Thrones S08E01, we're all enjoying the drama around Jon Snow's
Obviously the news creates turbulence for Jon's love life and for his humble position as Warden of the North or whatever. And Jon seems literal-minded enough that I would expect him to treat this news as a Big Deal, he doesn't have much moral flexibility unlike Cersei or even Jaime or Sansa. So it makes sense to me that he freaks out as soon as he learns the news.
Why does Bran insist that Jon needs to know this news? Bran is insightful enough even without his Greensight to know that this news will only cause (really poorly-timed) drama. It's not like Jon secretly wishes he could have a higher station in life; this news can only complicate and darken his life, plus it will prolong Westeros' political instability. And Bran doesn't seem like the type to care much about
potential aunt/nephew incest, nor about whether his brother gets to be king or not.
So why does Bran seem to feel urgency to make sure that Jon a) knows about, b) believes, and c) presumably does something about, this news?