Its satire. He doesn't advocate for anything near a proletarian ruled society, just the bare fucking minimum amount of welfare that is also provided by other 'developed' countries.

Ever hear the term 'Bernie killed rosa luxembourg'?

Its because he's a social democrat and not a socialist, and when push came to shove, it was the social democrats who betrayed the workers revolution in germany, and who killed or ousted our comrades accross europe.

The reason for this satirisation in particular is likely down to a joke about how the media tends to view him.