Unless there is some law broken I'm not sure what legal jeopardy incurs.
In the US, TTBOMK Hate Speech is not illegal or prohibited, thank God.
Saying that Jews should be killed is no different than Trump saying protesters at his rally should be taken out on a litter. I see absolutely no difference between what Trump did and what was said at the Charlottesville rally.
Behavior though can incur legal criminal ramifications. If the group prepared to round up Jews or attacked Jews or burned a synagogue then those individuals could be arrested.
But there are also civil sanctions possible. The organization could be sued in civil court if a actual case could be made that they caused physical or emotional trauma to an identified party. That was the tactic used to sue the KKK in the past which allowed financial sanctions against the organization and it's leaders and pretty much shut it down for a half century.