Don't know what they are exactly. It seems like they thought anybody can vote in a primary. They confuse primaries with the general election. They appear to be very politically naive and unrealistic. Like their mentor.
For example, nearly all of the Southern primaries were open primaries, so obviously it wasn't just Democrats voting in the Democratic primaries in those states.
I learned that from a Hillary Clinton supporter right here at DU.
And why is that a DUer suddenly thinks it cool to start sneering at the known difficulties in registering?