It is..for different reasons.

The reason people (Dave, Karkat) were against John/Vriska was because Vriska is a murderer and impulsive, and love violence too much. Basically, they were trying to warn John away to save him.

The reason Roxy is warning Jake, because we know nothing about the Alpha A-Vriska, is to try and push him to someone else (Jane or Dirk).

I think I like the reasoning for the Beta-verse better than the Alpha-verse.