She isn't popular among the right wing elites of the democratic party, but her policy proposals are popular among the left.
She is anti war, proposing a single payer health plan and her campaign is almost exclusively small dollar funded and not riddled with bribes.
She is more popular among the left than you realize.
Her supporters from the right are largely libertarians who agree with her completely logical anti war stance.
She is second left to only Bernie when it comes to left wing policy proposals.