I feel that you are over-reacting a bit. This is the first time I've heard him throwing such an organization under a bus. I mean BLM doesn't support him nor do other groups and organizations and he doesn't throw them under the bus.
What this does show is how much of an amateur he is. This is his first big boy campaign. Vermont is only a little more populated than Milwaukee and not even remotely as diverse. Him, and his supporters, are rookies while everyone int he Hillary camp are pros. You also have to keep in mind that he is the most radical candidate. And the law of politics say the further your supporters are in a spectrum, the more nuts they are. You are bound to get a few nutters out there. But to be honest this isn't that prevelant if you leave message boards. I mean sure there is facebook, but facebook is filled with crazy political images and quotes.
Well, I'm basing my throwing people under the bus based on his supporters, who we always hear don't reflect Bernie. Here, though, is a perfect example of how they do, in fact, reflect on him as a candidate. We've seen it over and over and over again. The Unions that endorse Hillary are nothing but sellouts. It's only the pure, liberal unions who endorse Bernie. Bernie has never once come out in support of any organization that his most vocal supporters have attacked. In politics, you have to do the "Planned Parenthood is a great organization. I can't wait to work with them as President" even if they don't endorse you. It's just common sense, let alone good politics.
As to the "it's only online," naw. Few months ago, my ex and I went around door to door canvassing for the mayoral race. I had a Hillary shirt and pin on. We asked for soft support for primary candidates. I was Bernsplained to more than once. One very lovely man berated us for not realizing that as gay men we should 100% Feel the Bern. We have a girl who is a hardcore Bernie fan who is completely....she's very passionate. We've never seen her before this year. I'm guessing we'll never see her again.
So my frustrations are not just based on real life. I'm used to internet activists. It's all good. The reason I want to see it stop is not because there's a chance, a very small chance, that Bernie could be our nominee. If this shit goes on in the GE, we're even more screwed than we'd already be.