whose supporters... have a tendency... to get violent... - even with each other, wants you to know he's not a Democrat. Democrats lost the last election. He thinks Trump is awful, so they should have won. Despite the fact that Dems nominated the person that Bernie ended up endorsing, he's doing his best to distance himself from the party.
He's an "independent," dontcha know. He loves that label, because it's more marketable than "devout socialist."
Anyway, he's been making the rounds lately. His appearances may slow down for a bit, since once of his volunteers tried to assassinate multiple prominent Republican congressmen, but prior to that incident he was showing up all over the place.