In my experience, people argue identity when they don’t want to argue policy. And the reason they don’t want to argue policy, usually, is that they’re wrong. But in arguing that everyone who disagrees with them is a racist, or a sexist, or a tool of Big Money, or whatever, the Democrats run the risk of self-destruction. This is basically what happened to the the Labour Party in Britain: A reliance on easy tropes that please the base but alienate other voters.
As Daniel Hannan notes: “When leftists attack the Tories, they’re not just having a go at 300 MPs, or 100,000 party members: They’re scorning everyone who has contemplated supporting the party. … How do you think this sort of thing goes down, not only with anyone who has ever voted Conservative, but with moderate people who, though they haven’t voted Tory themselves, have friends and family who have? When you adopt a bullying tone, you find that 1) voters don’t like it; 2) you solidify the other side’s core support; and 3) some people hide their voting intentions.”
Likewise, to many prominent Democrats and supporters have spent the past six years calling everyone who doesn’t agree with Obama a racist. Now some of the same folks are gearing up to call everyone who doesn’t support Clinton (or, perhaps, Warren, the backup-Hillary) a sexist. For instance, one group of Hillary supporters makes the preposterous claim that saying she is “out of touch” or ‘insincere” reflects a sexist worldview. This technique worked pretty well so far for Obama’s presidency, but it now seems to be wearing thin, even within the Democratic Party.