Who are you to judge who is a “true” Bernie Sanders supporter and who isn’t? Sounds like a “No True Scotsman” fallacy to me. The people who I see doing this daily are not bots or trolls, some of them have bylines in various low level lefty publications. Some of them have connections to known tiresome entities like Jordan Chariton. In fact, Mr. Chariton has been involved in some pretty nasty Twitter pile ons himself on people like Joy Reid and Neera Tanden.
I am sure it is embarrassing to realize that you aligned yourself with a movement that attracted a family sized package of nuts, but just because you didn’t come into contact with them, as a Berner, doesn’t mean they aren’t real.
There is evidence of bots and trolls engaging with the Sanders “movement” but that evidence is of them sending disinformation to Sanders supporters in Sanders social media groups, and those supporters, in turn, spreading said disinformation even after being told by group mods that the information was dubious.
Maybe you should just do some reflection on why you were drawn to a “movement” full of angry, vindictive cranks. And what on earth made you think, having looked at Bernie’s political history of failure, that he could have accomplished a single one of the things he campaigned on. And why you were attracted to a movement that was so predominately white and middle class.