Was identity politics a concrete thing or a construction? It seems HRC bet her entire campaign on that and it backfired spectacularly. Were they hoping that it would catch on? Based on what evidence?
Probably just hoping the Obama coalition would just automatically flow over to her, with no specific outreach on her part. Most of them did (the biggest share of popular votes) just not quite enough to win the Electoral College.
Either the voting machines were hacked, or she did an abysmal job in outreach... her hiring of David Brock (of Correct the Record) to essentially character-assassinate Sanders supporters might have had something to do with her loss - she won the battle then lost the war.