Why is Obama better off with the white working class than with Hillary?

Because the Democratic Party was more moderate when Obama was elected for the first time. The democratic coalition was more economically diverse at the time.

In fact, Obama has pushed the Democratic Party to go further left. He supported the BLM movement and played every chance with the race card, including condemning innocent cops. This is the reason why Democrats today can no longer win the white working class. Hillary did not help with that by not doing a good campaign.

The only current demographics of Democrats #MeToo and #ResistTrump can be won today are RINOs (nicknamed Republican suburban), women, millennia and minorities.