Jude is claiming that the heretics are unregenerate, they are not true Christian believers. Despite their claim to dreams and revelations given by the Spirit (Jude 1:8), the fruit of their lives show them to be those who do not have the Spirit (see Galatians 5:16–25). Immoral behaviour is sufficient evidence of the absence of the Spirit of God.1
19 It is these who cause divisions, worldly people, devoid of the Spirit.