In response to:
Bernie Sanders beating Trump is not realistic. The middle of the country is right of center, and is not ready to abandon free enterprise. You may say Bernie doesn't want to do that, but his rhetoric scares a great many. To be honest, nobody is really sure how far left Bernie is.
The only reason the establishment is panicking is because Bernie is going to lose to Trump.
Although Chris Matthews is an idiot, it does not seem like he compared Bernie to Nazis, but made a military comparison of the battle (for the nomination) being over.