I suspect the actual numbers of progressive Hillary haters is vastly overestimated. Before Bernie entered the race they were going to vote for Jill Stein anyway. They whipped themselves into a frenzy thinking he could actually become president and took to the internets expounding the virtues of Sanders' impossible goals. I expect their numbers will be more than nullified by the number of right leaning independents and moderate Republican voters who will refuse to vote for Trump.
