yeah she really fucked Jon over but we aren't supposed to take it that way
Well if you go back to the books. Sansa wouldn't actually be in the north with Jon. She'd be coming from the vale unannounced, and this battle would mark the first time a Stark sibling had seen each other since book one (not including bran and rickon traveling togeather in later books.) Combining Jon and Sansa's reunion with this battle would give it extra meaning however since the show used that plot point earlier in the season this battle had less impact then it is probably meant to have