Public campaign finance disclosures from Democratic presidential candidate Robert F. Kennedy Jr.’s campaign reveal numerous payments to individuals and groups whose ideologies differ significantly from traditional Democratic Party politics, a review by CNN’s KFile finds.
There’s no mechanism to throw him out of the party. Party membership in the US is completely informal, unlike many other countries. You’re basically a member if you say you are and there’s nothing anyone can do about it.
And even if there were a mechanism, the Kennedys are Democratic royalty.