I don't understand the Sanders' surrogates "post-Pete-dropout" strategy

[Jedi Guy]

51. Perhaps, but that doesn't address the point being made here.

The point is the behavior of his surrogates and, to a lesser degree, his supporters. Not every Berner is a member of the "dirtbag left." But that group is doing him and his candidacy no favors whatsoever with their behavior, as the OP rightly pointed out.

I personally don't find Bernie's policies/politics disagreeable. I think there's more than a bit of magical thinking involved and that it's not entirely realistic, but I don't think anything he's advocating is bad, per se.

I do find his behavior disagreeable. By this I mean his behavior during the last Democratic primary and its aftermath, in addition to running as a Democrat, then going back to being an independent, then running again as a Democrat. I interpret that behavior to mean he doesn't view himself as a member of the party, and simply views the party as a means to his end. It's a tool for him, no more and no less. I'm not keen on the way he hectors and waves his arms and wags his finger, so I find him personally disagreeable to at least some extent.

I also find the behavior of some of his surrogates and supporters to be extremely disagreeable, such as the examples the OP gave. I also find it comical that some subset of his followers behave like this, and then wonder (apparently in earnest) why so many people find their candidate and their movement to be off-putting.

TL;DR: It has very little to do with being rich and scared of his ideology for a lot of people. It has much more to do with how he and his movement behave towards others.