The article suggests the real answer to the question posed by the headline: it depends on who is defining a "hate group", but it's ruling class authorities who define peaceful protest groups as "hate groups" in order to discredit the latter and to defend their war crimes.
Based on the history of COINTELPRO activities, I think it is reasonable to suspect that one of the ruling class's secret agencies did call in a threat to the sheriff's office and identified him/herself as a member of the protest group.
The actions of the Juneau County Sheriff’s Department show a disturbing pattern that is reminiscent of the chilling effects of McCarthyism in the 1950s and the COINTELPRO activities of the FBI in the 1960s.