Why would anarchists, racists and all the other assorted mayhem makers protest/disrupt their own kind - Dems?
This is just a taste of things to come
Democrats struggle for unity as protesters swarm Netroots convention https://www.theguardian.com/us-news/2016/jul/17/democrats-netroots-convention-hillary-clinton-bernie-sanders
Same reason they did it in 1968.