Sanders is a nice guy for sure, but he can’t do the organizing we need to do (see below). It’s not something you can delegate.
Not sure how Dave came to this view on Sanders (he did mention his age and the fact that he doesn’t have apps on his phone), but Bernie’s campaign epitomizes grassroots, democratic organizing. The Intercept had an article on his campaign app and that app is translating into volunteers and donors at record numbers. It’s a big part of why I donated to his campaign. Of course, Sanders may waste all of this like Obama did, but I am willing to take that risk.